File readme for Standards for Digital Line Graphs (DLG) 
  documentation in the stdlg subdirectory of the public directory
                     -- 9/01/94 --

  Standards for DLG documentation is divided into three parts; 
  Part 1:  General (one file)
  Part 2:  Specifications (four files)
  Part 3:  Attribute Coding (eleven files)

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  FILE         DESCRIPTION

  readme       The ASCII formated file you are now reading

  *.txt        Documentation converted to ASCII format.

  *.wp5        Documentation in original WordPerfect format.

  *.ps         Documentation converted to PostScript format.

  *.tif        Image in Tagged Interchange File Format (TIFF)
               (Used for figures not contained within .asc 
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  stpt1all     Contents for the complete standard and Part 1:  
               General, containing series description and data
               sources, content, and structure                                 
 
  stpt2txt     Part 2:  Specifications, containing coordinate 
               systems, cell size and file extent, error 
               definition, data quality, and distribution 
               formats

  stpt2-2a     Part 2:  Specifications  Appendix A, containing
               standard DLG distribution format

  stpt2-2b     Part 2:  Specifications  Appendix B, containing
               optional DLG distribution format

  stpt2-2c     Part 2:  Specifications  Appendices C, D, and E,
               containing 1:2,000,000-scale graphic format, map
               projection parameters, and U.S. National Map 
               Accuracy Standards

  stpt3-tc     Part 3:  Attribute Coding introductory pages, 
               containing table of contents, lists of figures,
               tables, and pages

  stpt3-in     Part 3:  Attribute Coding sections containing 
               objectives, symbol references, and coding 
               structure (pp 3-1 through 3-14)

  stpt3-hp     Part 3:  Attribute Coding section entitled 
               Hypsography (pp 3-15 through 3-25)

  stpt3-hy     Part 3:  Attribute Coding section entitled 
               Hydrography (pp 3-26 through 3-67)

  stpt3-sc     Part 3:  Attribute Coding section entitled 
               Vegetative Surface Cover (pp 3-68 through 3-73)

  stpt3-nv     Part 3:  Attribute Coding section entitled 
               Non-Vegetative Features (pp 3-74 through 3-78)

 
  stpt3-bd     Part 3:  Attribute Coding section entitled 
               Boundaries (pp 3-79 through 3-91)

  stpt3-sm     Part 3:  Attribute Coding section entitled 
               Survey Control and Markers (pp 3-92 through 3-100)

  stpt3-tr     Part 3:  Attribute Coding section entitled 
               Transportation (pp 3-101 through 3-152)

  stpt3-ms     Part 3:  Attribute Coding section entitled 
               Manmade Features (pp 3-153 through 3-192)

  stpt3-pl     Part 3:  Attribute Coding section entitled 
               U.S. Public Land Survey System 
               (pp 3-193 through 3-247)

  fig2-2b      Figure for example diagram on p. 2B-19 
               (Part 2, Appendix B)

  fig3-1       Figure 3-1 on p. 3-39

  fig3-2       Figure 3-2 on p. 3-71

  National Mapping Program
  Technical Instructions





  Part 2
  Specifications


  Standards for
  Digital Line Graphs

  (Current version containing all changes through 3/1/94)





  Department of the Interior 
  U.S. Geological Survey
  National Mapping Division


                                 CONTENTS 
                                                                  
                                                                 Page
  2.    Specifications  . . . . . . . . . . . . . . . . . . . . . 2-1 
        2.l  Coordinate Systems . . . . . . . . . . . . . . . . . 2-l 
        2.2  Cell Size and File Extent  . . . . . . . . . . . . . 2-3 
        2.3  Error Definition . . . . . . . . . . . . . . . . . . 2-5 
             2.3.l  Blunders  . . . . . . . . . . . . . . . . . . 2-5 
             2.3.2  Systematic Errors . . . . . . . . . . . . . . 2-5 
             2.3.3  Random Errors . . . . . . . . . . . . . . . . 2-6 
             2.3.4  Standard Error  . . . . . . . . . . . . . . . 2-6 
        2.4  Data Quality . . . . . . . . . . . . . . . . . . . . 2-7 
             2.4.l  Lineage . . . . . . . . . . . . . . . . . . . 2-7 
             2.4.2  Positional Accuracy . . . . . . . . . . . . . 2-7 
             2.4.3  Attribute Accuracy  . . . . . . . . . . . . . 2-8 
             2.4.4  Edge Matching . . . . . . . . . . . . . . . . 2-8 
             2.4.5  Quality Control Flags . . . . . . . . . . . . 2-9 
             2.4.6  Logical Consistency . . . . . . . . . . . . . 2-ll
             2.4.7  Completeness  . . . . . . . . . . . . . . . . 2-ll
        2.5  Distribution Formats . . . . . . . . . . . . . . . . 2-12


                                APPENDICES 
  Appendix 2-A    Standard DLG Distribution Format  . . . . . . . 2A-l
  Appendix 2-B    Optional DLG Distribution Format  . . . . . . . 2B-l
  Appendix 2-C    l:2,000,000-Scale Graphic DLG Format  . . . . . 2C-l
  Appendix 2-D    Map Projection Parameters . . . . . . . . . . . 2D-l
  Appendix 2-E    U. S. National Map Accuracy Standards . . . . . 2E-l


                                  TABLES 
  Table 2.l  Comparison of Standard and Optional DLG Formats  . . 2-12


  2.          SPECIFICATIONS 
              Specifications for DLG data will be described by
              considering the following subject areas:  coordinate
              systems, cell size and extent, error definition, data
              quality and distribution format.

  2.l         COORDINATE SYSTEMS
              The positional descriptions for DLG data elements are
              expressed in  one of several coordinate systems,
              dependent upon the distribution  format selected.

              The DLG data in the standard distribution format are
              encoded using  an internal file coordinate system to
              minimize storage  requirements.  The characteristics of
              this system are as follows:

                 o  The coordinate system is Cartesian.
  
                 o  The origin (x=0, y=0) is at the center of the cell. 
                    Some older files will have their origin below and
                    to the left of the lower left corner of the cell.
  
                 o  The x axis of the coordinate system is parallel to
                    a  theoretical straight line connecting the
                    southwest and  southeast corners of the cell, and
                    the y axis is  perpendicular to that line.
  
                 o  One unit is equal to 0.00l inch at map scale.
  
                 o  The coordinate domain is limited to the range -
                    32768 to  +32767.

              The file header contains the parameters of a
              transformation which  can be used to convert the internal
              file coordinates to the ground  coordinate system in
              either Universal Transverse Mercator (UTM) for  l:24,000-
              and l:l00,000-scale DLG's, or Albers Conical Equal Area 
              for l:2,000,000-scale DLG's.
 
              The DLG data in the optional distribution format are
              expressed in  the units of the respective ground
              coordinate systems; that is,  meters in the UTM or Albers
              Conical Equal Area systems.
 
              The l:2,000,000-scale DLG data in the graphics
              distribution format  are expressed in geographic
              coordinates (latitude and longitude).   These values are
              expressed in degrees, minutes, and seconds.

  2.2         CELL SIZE AND FILE EXTENT 
              In general the large-scale DLG's are stored and
              distributed in  standard cells of 7.5-minutes of latitude
              by 7.5-minutes of  longitude.  Non-standard quadrangles
              which have a neatline extended  to accommodate overedge
              information, (e.g. along national  boundaries or in
              coastal areas) are collected as multiple 7.5- minute
              units.

              Of the l:24,000-scale data collected from l5-minute
              quadrangles,  the majority are digitized as four 7.5-
              minute units, and  distributed in standard 7.5-minute
              cells.  A few older data files,  collected from l5-minute
              quadrangles, were digitized in single l5- minute units,
              and are distributed in this format.  In Alaska, data 
              digitized from l:24,000/l:25,000-scale source material
              are stored  in cells varying from l0-minutes to l8-
              minutes of longitude, by  7.5-minutes of latitude,
              depending on the latitude of the cell.  Alaskan data
              digitized from l:63,360-scale source material are  stored
              in cells varying from 20-minutes to 36-minutes of
              longitude,  by l5-minutes of latitude, depending on the
              latitude of the cell.

              The intermediate-scale DLG's, covering the contiguous
              United States  and Hawaii, are to be distributed in
              groups of files that make up a  30- x 30-minute area of
              coverage, each grouping representing the  east or west
              half of a l:l00,000-scale source map.  Each 30-minute 
              area consists of a varying number of DLG files depending
              on the  category and the feature density.  The normal
              distribution group  will be four l5-minute files per 30-
              minute area.  If the feature  density of an area is such
              that the file size would exceed the  limitations of the
              processing software, then that 30-minute area  would be
              covered by sixteen 7.5-minute files.   In l986 the U.S. 
              Geological Survey released a preliminary version of
              l:l00,000-scale DLG's.  These data were packaged differently 
              than described above.  The distribution cells for the "roads
              and trails" portion of the  "transportation" overlay, and
              for the "hydrography" overlay,  consist of sixteen 7.5-
              minute files.  The "railroads" and  "miscellaneous
              transportation" portions of the "transportation"  overlay
              consist of single 30-minute files.  In northern Florida
              and  southern Georgia, the "railroads" and "miscellaneous 
              transportation" data may be in sixteen 7.5-minute files.

              The small-scale DLG's are distributed predominantly in
              multistate  cells, which approximate the National Atlas
              sectional maps.  The  total number of l:2,000,000-scale
              DLG cells is twenty-one; fifteen  for the conterminous
              United States, five for Alaska and one for  Hawaii.
  
              The data for each cell are encoded in multiple thematic
              categories.  Normally, there is one file per category. 
              However, due to software  limitations at the time of
              digitizing, some categories with a large  number of
              elements may be encoded in several files.

  2.3         ERROR DEFINITION 
              DLG data may contain errors of three types:  blunders,
              which should  be removed prior to entry to the data base;
              systematic errors,  occurring in a system-specific or a
              procedure-specific pattern; and  accidental errors, which
              are of a purely random nature and are  completely
              unpredictable.  Although all three types may be reduced 
              in magnitude by refinements in technique and precision,
              they never  can be completely eliminated.

  2.3.l       Blunders
              For DLG data, a blunder is an error of major proportions
              often exceeding 0.009 inch (3 times the standard error)
              in the x or y component directions.  This is the maximum
              error permitted for DLG data, and as such is easily
              identifiable.  Moreover, a blunder is an indication that
              the data collection  process has deteriorated beyond the
              level of simple systematic or  random errors.  Every
              effort is made to eliminate identifiable  blunders during
              processing and quality-control operations.  However, 
              despite design precautions, some blunders may remain.

  2.3.2       Systematic Errors
              Systematic errors are those errors that are introduced by 
              procedures or systems and typically are predictable but
              not easily  correctable.  These types of errors cause a
              bias or artifact in the  final product, but are generally
              not large enough to be classed as  blunders.  For DLG
              data, localized systematic errors could include 
              artifacts which are typical of raster-digitized data. 
              Unidentified  and uncorrected systematic errors are
              included in and contaminate  the accuracy statistics used
              to describe the final DLG.

  2.3.3       Random Errors
              Random errors are those errors considered to be
              observational in  nature or a result of limitations in
              measuring precision.  They are  caused by both system and
              human limitations.  Random errors  generally conform to
              a normal error distribution.

  2.3.4       Standard Error
              The standard error statistic is used to describe the
              horizontal accuracy of a DLG, encompassing both random
              and systematic errors introduced during production of the
              data.  The standard error is computed in both x and y
              component directions.

                 Standard error (SE) for the x or y direction is
                 defined as:

             where     Si = DLG x or y coordinate of a test point
                       St = true x or y coordinate of a test point
                        n = number of test points

                 The term St, "true" coordinate, refers to the "most
                 probable" coordinate value, since values are normally
                 derived from production map sources.

                 Accuracy is computed by comparison of the DLG
                 coordinate with true coordinates derived with a higher
                 order of accuracy.  Test points should be well defined
                 and well distributed and have "true" coordinates with
                 accuracies greater then the DLG accuracy criteria.

  2.4         DATA QUALITY 
              Five characteristics relating to digital data quality are
              included  as sections of a quality report.  The goal of
              this type of standard  is to allow the user the freedom
              to evaluate the usefulness of the  data for a given
              application, rather than applying a quantitative 
              threshold towards each characteristic.  The quality of
              Digital Line  Graph data can be described in terms of the
              following five  characteristics:  lineage, positional
              accuracy, attribute accuracy,  logical consistency, and
              completeness.  The procedures for  specifying and
              validating these characteristics are described in  Part
              5:  Quality Control and Verification.

  2.4.l       Lineage
              Lineage data generally provide information on the source
              of the  data file, collection procedures, processing
              steps, reference  systems, projection transformation
              parameters, data resolution, and  coordinate domain.
  
              DLG data carry some lineage information in the header
              record for  each file.  Format specifications designate
              specific fields for  lineage data elements (see
              Appendices 2-A and 2-B).  Additionally,  lineage data is
              described in related NMD Technical Instructions,  such as
              Procedure Manuals and Data Users Guides.
 
  2.4.2       Positional Accuracy
              DLG positional accuracy is based on the use of standard
              USGS  graphic products as the fundamental source for
              initial loading of  the NDCDB.  These source graphics are
              normally compiled to meet  National Map Accuracy
              Standards (see Appendix 2-E), where 90  percent of well-
              defined features are to be within 0.02 inches of 
              true mapped ground position.  The DLG positional error
              shall be less than or equal to 0.003 inches standard
              error in both the x and y component directions, relative
              to the source that was digitized.


              Positional consistency of DLG elements that span
              quadrangle edges  may be altered using edge alignment
              routines that result in  "snapping" together
              corresponding node and line elements that are  located
              within 0.020 inches of each other.  The maximum
              positional  adjustment for any node and associated line
              element would be 0.010  inches.

  2.4.3       Attribute Accuracy
              DLG data represent the source graphic and, therefore,
              data for a  given category will contain attribute codes
              that reflect the  information portrayed on the source. 
              All attribute codes of DLG  data in the NDCDB will agree
              within 98.5 percent to attribute codes  as described in
              Part 3 of this Standard:  Attribute Coding.

  2.4.4       Edge Matching
              Validation software provides for checking the edges of
              each  quadrangle against the edges of the four adjacent
              quadrangles.  Each edge of a DLG-3 is checked for
              positional and attribute matching  along the neatlines of
              the adjoining DLG-3 cells, providing that the surrounding
              data cells are available at the time the DLG-3 is 
              entered into the NDCDB.

              DLG's archived prior to implementation of edge matching 
              requirements may not have been edge checked.  All
              projects  authorized after April 30, l988 are required to
              meet current edge  matching specifications, both for
              joins internal to the project and  for joins to adjacent
              DLG's already existing in the NDCDB.  l00K DLG  data
              archived prior to implementation of edge matching
              requirements  are to be reworked to conform to current
              edge matching  specifications.

  2.4.5       Quality Control Flags
              Information in the header of the DLG-3 indicates the
              status of the  file with respect to the edge matching
              described above.  The four  status flags contain the
              status of the West, North, East, and South  edges of a
              DLG-3 as compared to the edges of the four adjoining 
              DLG-3 files.  Each of the four flags is followed by a
              status reason  code that explains the status of the four
              edges respectively.

              The possible status values for a DLG-3 entered into the
              NDCDB are: 
                    (blank) = no reason code set, ("unchecked" for
                                some earlier data sets)
                          0 = passed edge match check
                          l = alignment discontinuity
                          2 = attribute discontinuity
                          3 = attribute and alignment discontinuity

              The possible reason codes are: 
                    (blank) = no reason code set, ("unchecked" for
                                some earlier data sets)
                          4 = adjacent data do not exist
                          5 = adjacent data unavailable
                          6 = graphic discontinuity
                          7 = mismatch valid
                          8 = paneling unauthorized

              The following combinations of status flags and reason
              flags are  currently valid for the processing software.
                    blank, blank     blank, 4     blank, 5     blank,8
                    0,blank
                    l,6    l,7
                    2,6    2,7
                    3,6    3,7

              The following is a brief explanation of the reason flags.

              4 = adjacent data do not exist
              This flag is used with a status flag of blank
              (unchecked).  This  combination exists primarily for file
              edges which are adjacent to  areas unmapped within the
              series/scale of products being digitized,  e.g. coastal
              and international boundary locations.  This flag is  also
              used for U.S. Public Land Survey System (PLSS) file edges 
              which border areas of the country not having PLSS
              information.

              5 = adjacent data unavailable
              This flag is used with a status flag of blank
              (unchecked). It is  appropriate for edges adjacent to
              areas having similar source  material and data
              categories, but which have not been digitized and 
              archived.  A reason code with the value of 5 may be reset
              as the  adjoining data cell becomes available for edge
              match verification.

              6 = graphic discontinuity
              This flag indicates a discontinuity in classification or
              alignment  between features on adjacent graphics which
              were digitized as  represented.
  
              7 = mismatch valid
              This reason flag applies in the case of a linear graph
              element ending precisely on the neatline or having a
              reasonable attribute  value change as it crosses the
              neatline.  (e.g. A road changing  from third to fourth
              class at the neatline.)

              8 = paneling unauthorized
              This flag is used with the edge status flag of blank and
              indicates  that no authorization was in place for edge
              matching at the time  the data were archived.

              In the course of checking and aligning an edge it is
              possible to  encounter more than one reason for a
              mismatch status, such as both  valid and graphic
              discontinuities.  In such cases the reason flag  is to be
              set to indicate the "worst case", i.e. the reason 
              indicating the most serious problem with the edge and
              which in most  cases would require some degree of
              correction in the future.  For  the above example, the
              graphic discontinuity reason flag would be  set in
              preference to the mismatch valid flag.

  2.4.6       Logical Consistency
              Logical consistency describes topological fidelity
              internal to a  file.  Certain node-area-line
              relationships are collected or  generated to satisfy
              topological requirements.  Some of these  requirements
              include:  lines begin and end at nodes, lines connect  to
              each other at nodes, lines do not extend through nodes,
              left and  right areas are defined for each line element
              and are consistent  throughout the files and the lines
              representing the limits of the  file (neatline) are free
              of gaps.

  2.4.7       Completeness
              Completeness refers to the subset of features or objects 
              represented in the DLG in relation to the domain, which
              is the  source graphic.  The DLG for a given category of
              data will contain  at least the same level of content and
              detail shown on the source  graphic.

  2.5         DISTRIBUTION FORMATS 
              Digital Line Graph data are available in two distribution
              formats:  (l) standard and (2) optional.  DLG's from
              l:2,000,000-scale maps  are also available in a
              "graphics" format.
  
              The standard distribution format reflects design
              decisions intended  to minimize storage requirements. 
              Explicit topological linkages  are contained only in the
              line elements (starting node, ending  node, an area to
              the left of direction of travel, and an area to  the
              right of the direction of travel).

              The optional distribution format was designed to
              facilitate data  usage.  The topological relationships
              explicitly encoded include  starting node, ending node,
              area to the left of direction of  travel, and area to the
              right of the direction of travel for line  elements,
              bounding lines for area elements, and bounded lines for 
              node elements.  These files are typically larger than
              those in the  standard format but, for certain
              applications, can simplify  processing requirements.  For
              example, because topological linkages  are explicitly
              encoded for all line, node, and area elements, a  polygon
              data structure can be easily created.  These linkages 
              facilitate Geographic Information System (GIS)
              applications of DLG  data as well as generation of
              graphic products.

              The characteristics of the standard and optional DLG
              distribution  formats are compared in table 2.l.  The
              format and record contents  for the standard and optional
              formats are summarized in Appendices  2-A an 2-B,
              respectively.


                                   Table 2-1
           Comparison of DLG standard, optional and graphics formats
컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴퀼

                        Standard          Optional            Graphics

컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴퀼

   Character set        ASCII             ASCII                 ASCII

   Logical record       144 bytes         80 bytes              20 bytes
     length

   Physical record      Variable in       Variable in           Variable in
     length             multiples         multiples             multiples
     (block size)       of l44 bytes      of 80 bytes           of 20 bytes

   Coordinate system    Internal file     Ground planimetric:   Geographic
                        (thousandths of   UTM-24K and lOOK,     (latitude
                        a map inch)       Albers Conical        and
                                          Equal Area-2M         longitude)

   Topological          Contained only    Contained in node,    None (only
     linkages           in line elements  area, and line        contains
                                          elements              line
                                                                elements)

컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴퀼

              The l:2,000,000-scale graphics distribution format was
              designed for  use with the GS-CAM plotting package.  GS-
              CAM is a modified version  of the Cartographic Automatic
              Mapping (CAM) computer program.  A  graphic format file
              is organized by feature type, contains only  minimal
              descriptive information about each line, and the 
              relationship between lines is unspecified.  These files
              are not  topologically structured and contain no node or
              area elements.  The  format and record content for the
              l:2,000,000-scale graphics format  is summarized in
              Appendix 2-C.














                                  Appendix 2-B
                        Optional DLG Distribution Format

  In the optional DLG distribution format, topological linkages can
  be explicitly  encoded for node and area elements as well as for
  line elements.  The files are  physically comprised of ASCII
  characters organized into fixed-length logical  records of 80
  characters (bytes).  Bytes 1-72 of each record contain DLG data, 
  and bytes 73-80 may be blank or contain a record sequence number.

  The record types used in the optional DLG distribution format may
  be categorized  as header and data records.

  The following are considered header records:
       o   File identification and description records (variable
  record formats)
       o   Accuracy/miscellaneous records (not currently used)
       o   Control-point identification records
       o   Data-category identification records

  The following are considered data records:
       o   Node and area identification records
       o   Node-to-area linkage records*
       o   Node-to-line linkage records
       o   Area-to-line linkage records
       o   Area-to-node linkage records*
       o   Line identification records
       o   Coordinate string records (lines)
       o   Coordinate string records (areas)*
       o   Attribute code records
       o   Text records (not currently used)


  *Data distributed in optional format from the NDCDB will not
  contain these data  records.

  The actual sequence of records in an optional distribution format
  DLG file is as follows:

  1.    Header records
           Ten file identification and
             description records
           Accuracy records (not currently used)
           Control point identification records 
             (one per control point)
           Data category identification records
             (one per data category in the file)


  2.    Data records
           Node identification record
             Node-to-area linkage record(s)*       Repeated
             Node-to-line linkage record(s)        for each
             Attribute code record(s)              node within a
             Text record(s)                        data category


           Area identification record
             Area-to-node linkage record(s)*       Repeated
             Area-to-line linkage record(s)        for each
             Coordinate string record(s)*          area within a
             Attribute code record(s)              data category
             Text record(s)


           Line identification record              Repeated
             Coordinate string record(s)           for each
             Attribute code record(s)              line within a
             Text record(s)                        data category

  *Data distributed in optional format from the NDCDB will not
  contain these  records.

  Descriptions of the contents of the various types of records in an
  optional  distribution format DLG are contained in the following
  tables.





______________________________________________________________________________
______________________________________________
                                         FILE IDENTIFICATION AND DESCRIPTION
RECORDS
______________________________________________________________________________
______________________________________________
Record      Data                                Type                      
Starting   Ending
Number      Element     Contents          (Fortran Notation)  Format        Byte 
     Byte*          Comment               
______________________________________________________________________________
______________________________________________

1             1       Banner                    ALPHA          A72           1 
        72     " *** DLG-OPTIONAL FORMAT 
                                                                               
                PRODUCED BY USGS   PROSYS 
                                                                               
                RELEASE x.x.x  *** "

2             1       Name of digital           ALPHA          A40           1 
        40      The name of the digital data 
                      cartographic unit                                        
                cell followed by the State  
                                                                               
                two-character designators, 
                                                                               
                separated by hyphens.

---          ---      Filler                     ---           --            41 
       41      1 space                    

2             2       Date of original          ALPHA          A10           42 
       51      Year of original source
                      source material                                          
                material followed by 
                                                                               
                latest revision date if
                                                                               
                applicable; for example,
                                                                               
                1956, 1965.

2             3       Date qualifier            ALPHA          A1            52 
       52      Qualifier to discriminate
                                                                               
                revision date if present.
                                                                               
                (P=photorevision, I=photo-
                                                                               
                inspection, L=limited     
                                                                               
                revision, D=digital revision).

2             4       Scale of original         INTEGER*4      I8            53 
       60      Scale denominator of source
                      source material                                          
                material; for example, 24000,
                                                                               
                100000, or 2000000.

(Record 2, data element 5 and Record 3, data elements 1 through 18 apply to 24K
and 100K data files only.  These fields
contain filler in 2M data files.)

---          ---      Filler                     ---           ---           61 
       63      3 spaces

*The logical record length for the optional distribution format is 80 bytes, with
8 spaces of blank fill in bytes 73-80
of each record which may be used for a record sequence number.





______________________________________________________________________________
______________________________________________
                                         FILE IDENTIFICATION AND DESCRIPTION
RECORDS-continued
______________________________________________________________________________
______________________________________________
Record      Data                                Type                      
Starting   Ending
Number      Element     Contents          (Fortran Notation)  Format        Byte 
     Byte           Comment               
______________________________________________________________________________
______________________________________________

2             5       Sectional indicator       ALPHA          ---           64 
       66      Codes S, F, or T for
                      (100K files)                                             
                size of section, plus
                                                                               
                sequence number.

---          ---      Filler                     ---           ---           67 
       72      6 spaces

---          ---      Filler                     ---           ---           1 
        41      41 spaces

3             1       Largest primary           ALPHA          A4            42 
       45      Largest primary contour
                      contour interval                                         
                interval, followed by the
                                                                               
                interval unit (1=feet,
                                                                               
                2=meters).  Present only if
                                                                               
                two or more primary 
                                                                               
                intervals exist.  (selected
                                                                               
                categories)

3             2       Comma                     ALPHA          A1            46 
       46      comma separator

3             3       Largest primary           ALPHA          A4            47 
       50      Largest primary bathy-
                      bathymetric contour                                      
                metric interval, followed
                      interval                                                 
                by the interval unit (1=feet,
                                                                               
                2=meters, 3=fathoms). 
                                                                               
                Present only if two or more
                                                                               
                primary intervals exist.
                                                                               
                (selected categories)

---          ---      Filler                      ---          --            51 
       51      1 space






______________________________________________________________________________
______________________________________________
                                         FILE IDENTIFICATION AND DESCRIPTION
RECORDS
______________________________________________________________________________
______________________________________________
Record      Data                                Type                      
Starting   Ending
Number      Element     Contents          (Fortran Notation)  Format        Byte 
     Byte           Comment               
______________________________________________________________________________
______________________________________________

3             4       Smallest primary          ALPHA          A4            52 
       55      Smallest or only primary
                      contour interval                                         
                contour interval, followed
                                                                               
                by the interval unit as
                                                                               
                described above (selected
                                                                               
                categories).

3             5       Comma                     ALPHA          A1            56 
       56      comma separator

3             6       Smallest primary          ALPHA          A4            57 
       60      Smallest or only primary
                      bathymetric contour                                      
                bathymetric contour interval,
                      interval                                                 
                followed by the interval 
                                                                               
                unit as described above
                                                                               
                (selected categories).

3            7-9      Coded Flags               ALPHA          A1            61 
       63      3 flags for future use

3            10       Coded Flag                ALPHA          A1            64 
       64      Database coded edge flag
                                                                               
                for internal NMD use.

3            11       EDGEWS                    ALPHA          A1            65 
       65      Status flag for west edge,
                                                                               
                values are:  b=unchecked,
                                                                               
                0=passed, 1=alignment
                                                                               
                discontinuity, 2=attribute
                                                                               
                discontinuity, 3=attribute
                                                                               
                and alignment discontinuity.

3            12       EDGEWR                    ALPHA          A1            66 
       66      Reason for EDGEWS, values
                                                                               
                are:  b=no problem, 4=
                                                                               
                adjacent data do not exist,
                                                                               
                5=adjacent data unavailable,
                                                                               
                6=graphic discontinuity,
                                                                               
                7=graphic mismatch valid,
                                                                               
                8=paneling unauthorized.





______________________________________________________________________________
______________________________________________
                                         FILE IDENTIFICATION AND DESCRIPTION
RECORDS
______________________________________________________________________________
______________________________________________
Record      Data                                Type                      
Starting   Ending
Number      Element     Contents          (Fortran Notation)  Format        Byte 
     Byte           Comment               
______________________________________________________________________________
______________________________________________

3            13       EDGENS                    ALPHA          A1            67 
       67      Status flag for north edge, 
                                                                               
                values are b,0,1,2, or 3 as
                                                                               
                above.

3            14       EDGENR                    ALPHA          A1            68 
       68      Reason for EDGENS, values
                                                                               
                are b,4,5,6,7 or 8 as above.

3            15       EDGEES                    ALPHA          A1            69 
       69      Status flag for east edge,
                                                                               
                values are b,0,1,2, or 3
                                                                               
                as above.

3            16       EDGEER                    ALPHA          A1            70 
       70      Reason for EDGEES, values
                                                                               
                are b,4,5,6,7 or 8 as above.

3            17       EDGESS                    ALPHA          A1            71 
       71      Status flag for south edge,
                                                                               
                values are b,0,1,2, or 3
                                                                               
                as above.

3            18       EDGESR                    ALPHA          A1            72 
       72      Reason for EDGESS, values
                                                                               
                are b,4,5,6,7 or 8 as above.

4             1       DLG level code            INTEGER*2      I6            1 
        6     * Code=3, DLG-3

4             2       Code defining ground      INTEGER*2      I6            7 
        12    * 1Code=1 UTM (24K and 100K),
                      planimetric reference                                    
                Code=3 Albers Conical Equal
                      system                                                   
                Area (2M files)

4             3       Code defining zone in     INTEGER*2      I6            13 
       18    * 1Code for appropriate UTM
                      ground planimetric                                       
                zone (24K or 100K files), 
                      reference system                                         
                Code=9999 for 2M files


1See General Purpose Transformation Package software documentation for additional
information.

* Listed values reflect current NMD standard.






______________________________________________________________________________
______________________________________________ 
                                         FILE IDENTIFICATION AND DESCRIPTION
RECORDS
______________________________________________________________________________
______________________________________________
Record      Data                                Type                      
Starting   Ending
Number      Element     Contents          (Fortran Notation)  Format        Byte 
     Byte           Comment               
______________________________________________________________________________
______________________________________________

4             4       Code defining units       INTEGER*2      I6            19 
       24    * 1Code=2, meters
                      of measure for ground                                    
                              
                      planimetric coordinates
                      throughout the file                                      
                                          

4             5       Resolution                REAL*4         D18.11        25 
       42      The true ground distance
                                                                               
                corresponding to 0.001 inch
                                                                               
                at map scale.
                                                                               
                 Scale         Resolutions
                                                                               
                1:24,000         0.61  M
                                                                               
                1:25,000         0.635 M
                                                                               
                1:48,000         1.22  M
                                                                               
                1:62,500         1.587 M
                                                                               
                1:63,360         1.61  M
                                                                               
                1:100,000        2.54  M
                                                                               
                1:250,000        6.35  M
                                                                               
                1:2,000,000     50.80  M

4             6       Number of file-to-        INTEGER*2      I6            43 
       48      number=4
                      map transformation
                      parameters                                               
                                 

4             7       Number of accuracy/       INTEGER*2      I6            49 
       54      Currently=0, none included
                      miscellaneous records                                    
                                        

4             8       Number (n) of             INTEGER*2      I6            55 
       60      n=4  These points are
                      control points                                           
                     usually, but not 
                                                                               
                     always, a definition 
                                                                               
                     of the file coverage.    
                      


1See General Purpose Transformation Package software documentation for additional
information.

* Listed values reflect current NMD standard.





______________________________________________________________________________
______________________________________________
                                         FILE IDENTIFICATION AND DESCRIPTION
RECORDS
______________________________________________________________________________
______________________________________________
Record      Data                                Type                      
Starting   Ending
Number      Element     Contents          (Fortran Notation)  Format        Byte 
     Byte           Comment               
______________________________________________________________________________
______________________________________________

4             9       Number (q) of categories  INTEGER*2      I6            61 
       66    * q=1
                      in the DLG file                                          
                                          

4            10       Horizontal Datum          INTEGER*2      I3            67 
       69      Horizontal Datum of DLG
                                                                               
                  'b' or 0 = NAD 27
                                                                               
                         1 = NAD 83
                                                                               
                         2 = Puerto Rico
                                                                               
                         3 = Old Hawaiian
                                                                               
                         4 = Local (Astro)

4            11       Vertical Datum            INTEGER*2      I3            70 
       72      Vertical Datum of DLG
                                                                               
                  'b' or 0 = NGVD 29
                                                                               
                         1 = NAVD 88
                                                                               
                         2 = Local Mean Sea
                                                                               
                             Level

5-9           1       Projection parameters     REAL*8         3D24.15       1 
        72      Three parameters on each of
                      for map transformation                                   
                5 records (see Appendix 2-4).

10            1       Internal file-to-         REAL*4         4D18.11       1 
        72      X, Y coordinates resulting
                      map projection                                           
                from this transformation will
                      transformation                                           
                be expressed in the appro-
                      parameters                                               
                priate ground planimetric
                                                                               
                coordinate system.  If the
                                                                               
                x, y coordinates are already
                                                                               
                in the ground coordinate 
                                                                               
                system, the projection para-    
                                                                               
                meters will be:  A1=1.0,
                                                                               
                A2=0.0, A3=0.0, and A4=0.0.


* Listed values reflect current NMD standard.





______________________________________________________________________________
______________________________________________
                                         CONTROL POINT IDENTIFICATION RECORDS
______________________________________________________________________________
______________________________________________
Record      Data                                Type                      
Starting   Ending
Number      Element     Contents          (Fortran Notation)  Format        Byte 
     Byte           Comment               
______________________________________________________________________________
______________________________________________

1-n           1       Control-point label       ALPHA          A6            1 
        6       "SW," "NW," "NE," or "SE"
                                                                               
                for four quadrangle
                                                                               
                corners.  Field is padded
                                                                               
                with trailing blanks.

              2       Latitude                  REAL*4         F12.6         7 
        18      In degrees and decimal
                                                                               
                degrees.

              3       Longitude                 REAL*4         F12.6         19 
       30      In degrees and decimal
                                                                               
                degrees.

                      Filler                                                 31 
       36      6 spaces

              4       X coordinate              REAL*4         F12.2         37 
       48      In units in the appropriate
                                                                               
                zone of the ground plani-
                                                                               
                metric coordinate system.

              5       Y coordinate              REAL*4         F12.2         49 
       60      In units in the appropriate
                                                                               
                zone of the ground plani-
                                                                               
                metric coordinate system.

---         ---       Filler                     ---            ---          61 
       72      12 spaces





______________________________________________________________________________
______________________________________________
                                         DATA CATEGORY IDENTIFICATION RECORDS
______________________________________________________________________________
______________________________________________
Record      Data                                Type                      
Starting   Ending
Number      Element     Contents          (Fortran Notation)  Format        Byte 
     Byte           Comment               
______________________________________________________________________________
______________________________________________

1-q           1       Category name             ALPHA          A20           1 
        20      The first 4 characters are
                                                                               
                unique to USGS/NMD data.

              2       Attribute format codes    INTEGER*2      I4            21 
       24      Blank or zero (0) indicates
                                                                               
                default (2I6) attribute
                                                                               
                formatting in major-minor
                                                                               
                pairs.

              3       Highest node              INTEGER*2      I6            25 
       30      Number of nodes referenced
                      identification number.                                   
                in the file.

              4       Actual number of          INTEGER*2      I6            31 
       36      Only if the DCF is not  
                      nodes in file                                            
                packed, and the element
                                                                               
                ID numbers not compressed,
                                                                               
                will this number be dif-
                                                                               
                ferent from data element 3.

            ---       Filler                     ---           ---           37 
       37      1 space

              5       Presence of node-to-      INTEGER*2      I1            38 
       38      *0=node-area list not
                      area linkage records                                     
                included, 1=node-area
                                                                               
                list included.

              6       Presence of node-to-      INTEGER*2      I1            39 
       39      0=node-line list not
                      line linkage records                                     
                included, *1=node-line list
                                                                               
                included.

            ---       Filler                     ---           ---           40 
       40      1 zero or space
______________________________________________________________________________
______________________________________________

* Values marked are values from data distributed from the NDCDB.





______________________________________________________________________________
______________________________________________
                                         DATA CATEGORY IDENTIFICATION
RECORDS--continued
______________________________________________________________________________
______________________________________________
Record      Data                                Type                      
Starting   Ending
Number      Element     Contents          (Fortran Notation)  Format        Byte 
     Byte           Comment               
______________________________________________________________________________
______________________________________________

1-q           7       Highest area ID           INTEGER*2      I6            41 
       46      Number of areas refer-
                      number.                                                  
                enced in the file.       

              8       Actual number of areas    INTEGER*2      I6            47 
       52      Only if the DCF is not  
                      in file                                                  
                packed, and the element ID
                                                                               
                numbers not compressed,         
                                                                               
                will this number be different  
                                                                               
                from data element 7. 

            ---       Filler                     ---         ---             53 
       53      1 space

              9       Presence of area-to-      INTEGER*2      I1            54 
       54      *0=area-node list not
                      node linkage records                                     
                included, 1=area-node list
                                                                               
                included.

             10       Presence of area-to-      INTEGER*2      I1            55 
       55      0=area-line list not
                      line linkage records                                     
                included, *1=area-line list
                                                                               
                included.

             11       Presence of area-         INTEGER*2      I1            56 
       56      *0=area coordinates not
                      coordinate lists                                         
                included, 1=area coordinates
                                                                               
                included

             12       Highest line              INTEGER*2      I6            57 
       62      Number of lines
                      identification number                                    
                referenced in the file.

______________________________________________________________________________
______________________________________________

* Values marked are values for data distributed from the NDCDB.





______________________________________________________________________________
______________________________________________
                                         DATA CATEGORY IDENTIFICATION
RECORDS--continued
______________________________________________________________________________
______________________________________________
Record      Data                                Type                      
Starting   Ending
Number      Element     Contents          (Fortran Notation)  Format        Byte 
     Byte           Comment               
______________________________________________________________________________
______________________________________________

1-q          13       Actual number of          INTEGER*2      I6            63 
       68      Only if the DCF is not 
                      lines in file                                            
                packed, and the element ID
                                                                               
                numbers not compressed, will 
                                                                               
                this number be different from
                                                                               
                data element 12.        

            ---       Filler                     ---           ---           69 
       71      3 spaces

             14       Presence of line-         INTEGER*2      I1            72 
       72      0=line coordinates not
                      coordinate lists                                         
                included, *1=line coordinate
                                                                               
                list included.
______________________________________________________________________________
______________________________________________

* Values marked are values for data distributed from the NDCDB.





______________________________________________________________________________
______________________________________________
                                         NODE AND AREA IDENTIFICATION RECORDS
______________________________________________________________________________
______________________________________________
Record      Data                                Type                      
Starting   Ending
Number      Element     Contents          (Fortran Notation)  Format        Byte 
     Byte           Comment               
______________________________________________________________________________
______________________________________________
              1       Record type               ALPHA          A1            1 
        1       "N" or "A"

              2       Element internal          INTEGER*2      I5            2 
        6       Number is positive and seq-
                      ID number                                                
                uential from 1-n within each
                                                                               
                element type, where n is the
                                                                               
                highest element ID number.

              3       Coordinates of node       REAL*4         2F12.2        7 
        30      The area point is usually,
                      point or representative                                  
                but not always within the
                      point for area                                           
                polygon it represents.

              4       Number of elements in     INTEGER*2      I6            31 
       36                                
                      an area list (for nodes),                                
                                            
                      or a node list (for areas)                               
                         

              5       Number of elements in     INTEGER*2      I6            37 
       42      Number of line segments that
                      line list                                                
                intersect at the node or, for
                                                                               
                areas, line segments plus 
                                                                               
                number of islands.

              6       Number of x,y or          INTEGER*2      I6            43 
       48      For area records only,
                      lat-long points in                                       
                blank for node records.
                      area-coordinate list                                     
                         

              7       Number of attribute       INTEGER*2      I6            49 
       54                         
                      code pairs listed                                        
                             

              8       Number of text            INTEGER*2      I6            55 
       60      Zero (0).  There are no 
                      characters listed                                        
                text attributes for DLG data.

              9       Number of islands         INTEGER*2      I6            61 
       66      For area records only, blank
                      within area                                              
                for node records.            

---         ---       Filler                     ---           ---           67 
       72      6 spaces                   





NODE-TO-AREA LINKAGE RECORDS

FORTRAN FORMAT (12I6), for each node:  The list consists of area internal ID
numbers (which appear in bytes 2-6 of the area
identification records) of all the areas that are adjacent to that node.  There
is no logical order to the list.

NODE-TO-LINE LINKAGE RECORDS

FORTRAN FORMAT (12I6), for each node:  The list consists of line internal ID
numbers (which appear in bytes 2-6 of the line
identification records) of all the lines that connect to that node.  The lines
that begin at this node are included in the list
as positive ID numbers.  The lines which terminate at this node are included as
negative ID numbers.  There is no logical order
to the list.

AREA-TO-NODE LINKAGE RECORDS

FORTRAN FORMAT (12I6) for each area:  The list consists of node internal ID
numbers (which appear in bytes 2-6 of the node
identification records) of all nodes that are adjacent to that area.  For those
areas with islands, the number zero, used as a
delimiter, marking the beginning of each island sublist.  The format of this list
is the same as the Area-Line list below.

AREA-TO-LINE LINKAGE RECORDS

FORTRAN format (12I6), for each area:  The list consists of line internal ID
numbers (which appear in bytes 2-6 of the line
identification records) of all lines that bound that area and lines which are
adjacent to an area.  For those areas with islands
(indicated by bytes 61-66 of the area's first record), the number zero, used as
a delimiter, marking the beginning of islands. 
Lines with this area to the right are included as positive ID numbers.  Lines
with this area to the left are included as negative
ID numbers.  The list is ordered clockwise around the perimeter of the area and
counterclockwise around each island, if any
(counterclockwise around an island of an area is still a clockwise direction in
reference to the area itself).  The number zero
is inserted in the list before each island sublist.  Lines that do not contribute
to the effective boundary of the area (those
having both their area left and area right assigned to the same area) are not
considered bounding lines.  Therefore, these lines,
while still present in the file, will not be referenced in the area-to-line
linkage records.





______________________________________________________________________________
______________________________________________
                                                LINE IDENTIFICATION RECORDS
______________________________________________________________________________
______________________________________________
Record      Data                                Type                      
Starting   Ending
Number      Element     Contents          (Fortran Notation)  Format        Byte 
     Byte           Comment               
______________________________________________________________________________
______________________________________________

              1       Record type                              A1            1 
        1       "L"

              2       Element internal ID number               I5            2 
        6       Number is positive and seq-
                                                                               
                uential from 1-n within each
                                                                               
                element type, where n is the
                                                                               
                highest element ID number.

              3       Starting node                            I6            7 
        12      Internal ID number.  Refers
                                                                               
                to data element 2 of the   
                                                                               
                node identification record.

              4       Ending node                              I6            13 
       18      Internal ID number.  Refers
                                                                               
                to data element 2 of the
                                                                               
                node identification record.

              5       Left area                                I6            19 
       24      Internal ID number.  Refers
                                                                               
                to data element 2 of the   
                                                                               
                area identification record.

              6       Right area                               I6            25 
       30      Internal ID number.  Refers
                                                                               
                to data element 2 of the   
                                                                               
                area identification record. 

            ---       Filler                                   ---           31 
       42      12 spaces

              7       Number of x,y coordinate                 I6            43 
       48      Number of coordinate
                      pairs listed                                             
                pairs listed.

              8       Number of attribute                      I6            49 
       54                                
                      code pairs listed                                        
                                         
                                                                               
                              

              9       Number of text characters listed         I6            55 
       60      Zero (0).  There are no text
                                                                               
                attributes for DLG data.





LINE COORDINATE STRING RECORDS

FORTRAN format (3(2F12.2)):  The coordinates are in appropriate units in the
designated ground planimetric coordinate system
(usually meters in UTM), or in internal file units.

CODE RECORDS

As major-minor code attribute pairs, FORTRAN format (6(2I6)):  Within each pair,
the first integer is the major code and the second
integer is the minor code.  Each major and minor code is a one-to-four-digit
integer, right justified within the six-byte field.

AREA COORDINATE STRING RECORDS

FORTRAN FORMAT (3(2F12.2)):  The last data element in the area identification
record contains the number of islands within the area. 
If this number is greater than zero, the following convention applies to the Area
Coordinate list: 

      The coordinates of the outside boundary of the area are listed first.  The
first coordinate of the outside boundary is
      repeated to signal the closure of this ring.  Next, the coordinates of one
of the islands are listed.  The first coordinate
      of this boundary is repeated, again signaling the end of this ring.  Next,
the first coordinate of the outside boundary
      is listed as a ring delimiter.  This process is repeated until the
coordinates of the boundaries of all the islands are
      listed.  The coordinates in this list are ordered so that the area being
referenced is always to the right of the boundary
      described by the sequence of coordinates.  Therefore, the list is ordered
clockwise around the perimeter of the area and
      counterclockwise around each island, if any.  The common coordinates
between adjacent ring lines are only listed once,
      except for the beginning and ending of a ring.





EXAMPLE 1:  (A diagram illustrating this example may be found following the
text.)

Area line list (for area 41):  10, 11, -12, 0, 14, -15, 0, -18, 0, -82, -84, 21 


Area node list (for area 41):  30, 31, 32, 0, 33, 34, 0, 35, 0, 36, 77, 76

Area coordinate list explanation:

     o  Outside ring coordinates:
        (20, 50), (40, 60), (60, 50), (70, 40), (60, 20), (40, 10), (30, 10),
(20, 30), (10, 40), (20, 50)  starting point  
        [                   (      ]                      [      )             
                         ]  of outside ring

                     L10                           L11                         
       L12                  separate rings)

     o  1st island ring coordinates:
        (25, 45), (28, 39), (34, 43), (34, 48), (30, 50), (25, 45), (20, 50)   
      ring closes       first coordinate 
        [                   (     ]                             )              
      itself            in outside ring  
   
                  L14                           L15                            
                     delimiter 

     o  next island ring coordinates:
        (30, 30), (30, 20), (40, 20), (40, 30), (30, 30), (20, 50)      ring
delimiter
        [                                              ]

                            L18       

     o  last island ring coordinates:
        (50, 40), (50, 30), (48, 22), (58, 24) (60, 35), (55, 45), (50, 40), (20,
50)     ring delimiter must be
        [         (       ]                    [       )                   ]   
          present at end of list if

                L82                 L84                       L21              
         islands are present.
                                                      

Note:  Since lines 80, 85, and 86 have area 41 as both their area left and area
right, they are not considered 
       "boundaries" of area 41.  Therefore, they are not used to build the area
line list, area node list, 
       or area coordinate list for this area.


Complete area coordinate list:
(20, 50), (40, 60), (60, 50), (70, 40), (60, 20), (40, 10), (30, 10), (20, 30),
(10, 40), (20, 50), 
(25, 45), (28, 39), (34, 43), (34, 48), (30, 50), (25, 45), (20, 50), 
(30, 30), (30, 20), (40, 20), (40, 30), (30, 30), (20, 50), 
(50, 40), (50, 30), (48, 22), (58, 24), (60, 35), (55, 45), (50, 40), (20, 50)


  National Mapping Program
  Technical Instructions





  Part 3
  Attribute Coding


  Standards for
  Digital Line Graphs

  (Current version containing all changes through 4/7/94)





Department of the Interior
U.S. Geological Survey
National Mapping Division
                                CONTENTS

                                                                    Page
  3.  Attribute Coding . . . . . . . . . . . . . . . . . . . . . . . 3-1
           3.1   Objectives. . . . . . . . . . . . . . . . . . . . . 3-1
           3.2   Symbol References . . . . . . . . . . . . . . . . . 3-3
           3.3   Coding Structure. . . . . . . . . . . . . . . . . . 3-4
                 3.3.1  Major Code Description . . . . . . . . . . . 3-6
                 3.3.2  Minor Code Description . . . . . . . . . . . 3-8
                 3.3.3  Common Attribute Codes . . . . . . . . . . .3-10
           3.4   Hypsography--Major code 020 . . . . . . . . . . . .3-15
                 3.4.1  General Principles . . . . . . . . . . . . .3-15
                 3.4.2  Node Attribute Codes . . . . . . . . . . . .3-17
                 3.4.3  Area Attribute Codes . . . . . . . . . . . .3-17
                 3.4.4  Line Attribute Codes . . . . . . . . . . . .3-17
                 3.4.5  Single-Point Attribute Codes . . . . . . . .3-21
                 3.4.6  General Purpose Attribute Codes. . . . . . .3-22
                 3.4.7  Descriptive Attribute Codes. . . . . . . . .3-22
                 3.4.8  Parameter Attribute Codes. . . . . . . . . .3-24
           3.5   Hydrography--Major Code 050 . . . . . . . . . . . .3-26
                 3.5.1  General Principles . . . . . . . . . . . . .3-26
                 3.5.2  Node Attribute Codes . . . . . . . . . . . .3-32
                 3.5.3  Area Attribute Codes . . . . . . . . . . . .3-34
                 3.5.4  Line Attribute Codes . . . . . . . . . . . .3-43
                 3.5.5  Single-Point Attribute Codes . . . . . . . .3-46
                 3.5.6  General Purpose Attribute Codes. . . . . . .3-48
                 3.5.7  Descriptive Attribute Codes. . . . . . . . .3-60
                 3.5.8  Parameter Attribute Codes. . . . . . . . . .3-65
           3.6   Vegetative Surface Cover--Major Code 070. . . . . .3-68
                 3.6.1  General Principles . . . . . . . . . . . . .3-68
                 3.6.2  Node Attribute Codes . . . . . . . . . . . .3-69
                 3.6.3  Area Attribute Codes . . . . . . . . . . . .3-69
                 3.6.4  Line Attribute Codes . . . . . . . . . . . .3-72
                 3.6.5  Single-Point Attribute Codes . . . . . . . .3-73
                 3.6.6  General Purpose Attribute Codes  . . . . . .3-73
                 3.6.7  Descriptive Attribute Codes  . . . . . . . .3-73
                 3.6.8  Parameter Attribute Codes  . . . . . . . . .3-73
           3.7   Non-Vegetative Features--Major Code 080 . . . . . .3-74
                 3.7.1  General Principles . . . . . . . . . . . . .3-74
                 3.7.2  Node Attribute Codes . . . . . . . . . . . .3-75
                 3.7.3  Area Attribute Codes . . . . . . . . . . . .3-75
                 3.7.4  Line Attribute Codes . . . . . . . . . . . .3-77
                 3.7.5  Single-Point Attribute Codes . . . . . . . .3-77
                 3.7.6  General Purpose Attribute Codes  . . . . . .3-78
                 3.7.7  Descriptive Attribute Codes  . . . . . . . .3-78
                 3.7.8  Parameter Attribute Codes  . . . . . . . . .3-78
           3.8   Boundaries--Major Code 090. . . . . . . . . . . . .3-79
                 3.8.1  General Principles . . . . . . . . . . . . .3-79
                 3.8.2  Node Attribute Codes . . . . . . . . . . . .3-82
                 3.8.3  Area Attribute Codes . . . . . . . . . . . .3-83
                 3.8.4  Line Attribute Codes . . . . . . . . . . . .3-88
                 3.8.5  Single-Point Attribute Codes . . . . . . . .3-90
                 3.8.6  Parameter Attribute Codes. . . . . . . . . .3-90

           3.9   Survey Control and Markers--Major Code 150. . . . .3-92
                 3.9.1  General Principles . . . . . . . . . . . . .3-92
                 3.9.2  Node Attribute Codes . . . . . . . . . . . .3-95
                 3.9.3  Area Attribute Codes . . . . . . . . . . . .3-95
                 3.9.4  Line Attribute Codes . . . . . . . . . . . .3-95
                 3.9.5  Single-Point Attribute Codes . . . . . . . .3-97
                 3.9.6  General Purpose Attribute Codes. . . . . . .3-99
                 3.9.7  Descriptive Attribute Codes. . . . . . . . .3-99
                 3.9.8  Parameter Attribute Codes. . . . . . . . . .3-99
           3.10  Transportation--Major Codes 170, 180, 190 . . . . 3-101
                 3.10.1 General Principles . . . . . . . . . . . . 3-101
                 3.10.2 Instructions for the Use of Attribute Codes
                          for Roads and Trails . . . . . . . . . . 3-111
                 3.10.3 Instructions for the Use of Attribute Codes
                          for Railroads. . . . . . . . . . . . . . 3-133
                 3.10.4 Instructions for the Use of Attribute Codes
                          for Pipelines, Transmission Lines, and
                          Miscellaneous Transportation Features. . 3-143
           3.11  Manmade Features--Major Code 200. . . . . . . . . 3-153
                 3.11.1 General Principles . . . . . . . . . . . . 3-153
                 3.11.2 Node Attribute Codes . . . . . . . . . . . 3-159
                 3.11.3 Area Attribute Codes . . . . . . . . . . . 3-159
                 3.11.4 Line Attribute Codes . . . . . . . . . . . 3-166
                 3.11.5 Single-Point Attribute Codes . . . . . . . 3-170
                 3.11.6 General Purpose Attribute Codes  . . . . . 3-173
                 3.11.7 Descriptive Attribute Codes  . . . . . . . 3-189
                 3.11.8 Parameter Attribute Codes. . . . . . . . . 3-192

           3.12  U. S. Public Land Survey System--Major Code 300 . 3-193
                 3.12.1 Background . . . . . . . . . . . . . . . . 3-193
                 3.12.2 General Principles . . . . . . . . . . . . 3-194
                 3.12.3 Node Attribute Codes . . . . . . . . . . . 3-200
                 3.12.4 Area Attribute Codes . . . . . . . . . . . 3-208
                 3.12.5 Line Attribute Codes . . . . . . . . . . . 3-234
                 3.12.6 Single Point Attribute Codes . . . . . . . 3-239
                 3.12.7 Parameter Attribute Codes  . . . . . . . . 3-239
                 3.12.8 Irregular Rectangular Surveys in Ohio &
                          Indiana  . . . . . . . . . . . . . . . . 3-241



                                  FIGURES


  Figure                                                            Page
  3-1       Attribute and parameter coding for hydrography 
              coincident with vegetative surface cover . . . . . . .3-39
  3-2       Attribute and parameter coding for woods, submerged
              woods, wooded swamp and submerged wooded swamp . . . .3-71

                                   TABLES


  Table                                                             Page
   3-1       Summary of attribute code changes . . . . . . . . . . . 3-5
   3-2       Current major attribute codes . . . . . . . . . . . . . 3-7
   3-3       Origins of the U.S. rectangular surveys . . . . . . . 3-211
   3-3a      Origins of U.S. private surveys in Ohio . . . . . . . 3-213
   3-4       Township duplicates . . . . . . . . . . . . . . . . . 3-216
   3-5       Named land grant codes. . . . . . . . . . . . . . . . 3-220




  (Current version containing all changes through 11/15/93)


  3.1       OBJECTIVES
            Digital cartographic data produced by the National Mapping
            Program are intended to support the requirements of a
            broad spectrum of users, not only for traditional
            cartographic products, but also for input to geographic
            information systems, for the production of graphics, and
            for automated spatial analyses.  The data are collected in
            logical categories that comprise unique themes, not
            necessarily corresponding to traditional feature
            separates.

            Attribute codes, also called feature codes or
            classification attributes, are used to describe the
            physical and cultural characteristics of digital line
            graph (DLG) data elements:  nodes, areas, and lines.  Part
            3 describes the general characteristics of the DLG coding
            scheme, defines the attribute codes used in each DLG data
            category, and provides guidance for the standardized
            application of these codes in the digitizing process.
 
            In the initial effort of building the DLG data base, the
            primary source materials used for data collection are
            published 1:24,000-, 1:25,000-, and 1:100,000-scale
            topographic maps.  Field notes, aerial photographs, and
            compilation materials are not normally used directly.  It
            is therefore necessary to prescribe the use of attribute
            codes based on information depicted on published maps. 
            Every standard cartographic symbol will have an attribute
            code number, although there are situations where more than
            one attribute code will be required to fully describe a
            feature.  The DLG file will reflect the level of detail or
            feature generalization of the source map.  Therefore, many
            of the attribute codes are scale dependent and may not
            apply to a given source.

   Attribute codes are formulated according to the following guidelines:

              o  Minimize redundant information.

                 Generally, attribute codes are not assigned to a
                 feature if they can be derived from relationships to
                 adjacent features. For example, in the U.S. Public
                 Land Survey System (PLSS) category, township extremity
                 lines are not explicitly coded because this attribute
                 can be derived by examining the attributes of the two
                 areas that bound each line.

              o  Provide sufficient reference information to support
                 integration with large, multipurpose data bases. 
  
                 Many organizations maintain sets of mission-specific
                 thematic or statistical data that are combined with
                 cartographic base categories for both display and
                 analysis.  The DLG attribute coding scheme attempts to
                 facilitate this process by the support of a variable
                 number of attributes assigned to each feature, which
                 creates an open-ended structure to which a user may
                 add information, and by the use of established Federal
                 Information Processing Standard (FIPS) codes, where
                 available.
 
              o  Describe the interrelations between cartographic
                 elements.
  
                 The interrelationships between cartographic elements
                 are expressly encoded where appropriate.
  
                 For example, the "right bank" and "left bank" of a
                 river are designated rather than "bank" so that the
                 direction of flow can be determined.  A node is coded
                 at the beginning of a single line stream for the same
                 reason.

  3.2       SYMBOL REFERENCES
            When an attribute code is specifically related to a
            standard cartographic symbol, the symbol number is cited. 
            Symbol numbers refer to the following National Mapping
            Program Technical Instructions:

            (A)  Standards for 1:24,000- and 1:25,000-Scale Quadrangle
                 Maps, Part 6:  "Publication Symbols (Supplement)" -
                 December 1981.
  
            (B)  Standards for 1:100,000-Scale Quadrangle Maps, Part 4: 
                 "Publication Symbols" - May 1984.

            (C)  Standards for 1:24,000- and 1:25,000-Scale Quadrangle
                 Maps, Part 5:  "Publication Symbols" - May 1984.
  
            (D)  Standards for Provisional Edition Maps, 1:24,000- and
                 1:25,000-Scale, Part 2:  "Compilation Symbols" -
                 January 1982.
  
            In reference A the symbol number is cited.  In references
            B and C, the feature separate number and item number are
            attached to form a symbol number, for example, 145.2.  In
            reference D, the section number and item number are
            attached to form a symbol number, for example, 2103.01. 
            Throughout Part 3, each symbol number cited will have the
            reference letter in parentheses after it, for example,
            207(A), 145.2(B), 512.61, 545.5 (C), or 2103.01(D).  When
            a symbol has been eliminated from the Technical
            Instructions, it may be referred to as an "old" symbol,
            for example, old symbol 512.57(C).

  3.3       CODING STRUCTURE
            Each attribute code identifies the general data category
            to which a feature belongs, as well as the specific nature
            of the feature.  Codes also provide additional descriptive
            information.  Many features are uniquely described by a
            single attribute code.  Others may require two or more
            codes for a complete description.  If multiple attributes
            are needed to describe a feature, their ordering is not
            significant, except in the case of highway route numbers. 
            It is not necessary for each element to have associated
            attributes.

            A DLG attribute code is composed of two distinct numeric
            fields:  a three digit major code, the first two digits of
            which identify the data category to which the feature
            belongs, and a four digit minor code, which specifically
            describes the feature.

            This document supersedes "Computer Files and Attribute
            Codes for Digital Line Graphs" (January 1980, revised
            February 1982) as well as National Mapping Program Data
            Users Guide 1,  "Digital Line Graphs from 1:24,000-scale
            Maps" (1990), National Mapping Program Data Users Guide 2: 
            "Digital Line Graphs from 1:100,000-scale Maps" (1989),
            and National Mapping Program "Digital Line Graph Attribute
            Coding Standards" (1985) in defining attribute codes to be
            used for DLG's.  In this document, some data category
            names are changed.  Also, some attribute codes replace
            previously defined codes, some are newly defined, and some
            are modified.  All are explained in greater detail than in
            the previous documents.  The changes are summarized in
            Table 3-1 by major code.  In the categories where the
            major code was changed, the minor codes were changed.
  




                                   Table 3-1
                       Summary of attribute code changes

     Current    Prior      Category                Type of Change
     major      major
     code       code

     020        020        Hypsography             Replacement of minor
                                                   codes
     ---        030        Streams                 Included in 050
                                                   Hydrography
     ---        040        Water Bodies            Included in 050
                                                   Hydrography
     ---        050        Wetlands                Included in 050
                                                   Hydrography
     ---        060        Coastal Features        Included in 050
                                                   Hydrography
     050        ---        Hydrography             Newly defined
     070        ---        Vegetative Surface
                             Cover                 Newly defined
     080        ---        Non-Vegetative
                             Features              Newly defined
     090        090        Boundaries              Expanded codes,
                                                   definitions
     150        ---        Survey Control
                             and Markers           Newly defined
     170        100        Roads and Trails        Replacement
     180        110        Railroads               Replacement
     ---        120        Water Navigation        Included in 050
                                                   Hydrography
     190        130        Pipelines,
                             Transmission Lines,
                             and Miscellaneous
                             Transportation
                             Features              Replacement
     200        140        Manmade Features        Replacement
     300        ---        U.S. Public Land
                             Survey System (PLSS)  Expanded codes, 
                                                   definitions

  3.3.1     Major Code Description
            The first two digits of the major code uniquely identify
            the data category to which the described element belongs. 
            Table 3-2 lists currently used major codes and the
            categories they represent.

            The third digit of the major code is used to designate the
            interpretation of the minor code in two ways:
  
                 o  if it is zero, the minor code numbers represent a
                    description or classification of a specific
                    feature, for example, 050 0300, which identifies a
                    spring.
  
                 o  if it is not a zero, the minor code numbers have
                    special interpretations as a parameter. The
                    interpretation to be applied is given for each
                    category.  For example, 055 ---- is used to encode
                    the value of a river mile mark.
 

                                   Table 3-2
                         Current major attribute codes

               Major code                       Base category
                  020         Hypsography
                  050         Hydrography
                  070         Vegetative Surface Cover
                  080         Non-Vegetative Features
                  090         Boundaries
                  150         Survey Control and Markers
                              Transportation systems
                  170               Roads and Trails
                  180               Railroads
                  190               Pipelines, Transmission Lines, and
                                    Miscellaneous Transportation
                                    Features
                  200         Manmade Features

                                    Nonbase Category
                  300         U.S. Public Land Survey System

  3.3.2     Minor Code Description
            The first digit of the minor code is normally zero.  If it
            is not a zero, the number is used as a modifier to provide
            additional information about a feature.  For example, code
            302 0001 identifies township 1 north as a full township;
            but code 302 4002 identifies township 2 north as a half
            township in the PLSS.

            The remaining three digits are normally used to classify
            specific features.  The type of element described by a
            particular code can be determined from the value of these
            digits:

                 o  node:  001 - 099
                 o  area:  100 - 199
                 o  line:  200 - 299
                 o  single-point (degenerate line):  300 - 399
                 o  general purpose codes (apply to multiple feature
                    types): 
                    400-499
                 o  descriptive codes:  600-699
  
            Exceptions to this scheme are discussed below as well as
            noted in the specific code descriptions.
  
            The general purpose codes are used on features that may be
            digitized as a node, area, or line depending on the size
            and position of the feature.  The descriptive codes are
            used with another code to qualify its meaning.  General
            purpose and descriptive attribute codes were added to the
            coding scheme in 1982.  They are, therefore, not used in,
            or defined for, the two categories collected most heavily
            before 1982, U.S. Public Land Survey System and
            boundaries.

            The last three digits of the minor codes may also be used
            as a parameter code.  Parameters are used when a minor
            code can legitimately assume a range of values, for
            example, water elevation or highway route number.  The
            meaning of a parameter code is derived from the (non zero)
            third digit of the major code.  Parameters are both
            category and feature specific.

  3.3.3     Common Attribute Codes
            In general, the meaning of an attribute code is unique to
            the feature it describes.  There are, however, several
            exceptions.

            Outside area (000 0000)
            Each DLG provides a coherent description of that portion
            of the earth's surface covered by a 1:24,000-scale,
            7.5-minute cell, or a specific subdivision of another
            scale source.  To maintain topological consistency and to
            facilitate the combination (integration) of multiple
            DLG's, the area outside the cell is specifically
            identified for each DLG.  This area element, which must be
            the first area present in each data category, is assigned
            a single attribute code with major and minor codes both
            equal to zero.

            Photorevised features (XX0 0000)
            Map features obtained by photorevision methods are printed
            in purple on 1:24,000- and 1:25,000-scale maps.  They are
            described by attribute codes from the appropriate
            category.  In addition, a code consisting of major code
            XX0, where XX are the two digits uniquely identifying the
            data category, and a minor code of zero, will also be
            attached.  The photorevised code can be applied to any
            feature types but can not be used alone except as a line
            code for a photorevised line in the Boundaries category. 
            For example:
            a.  A class 3 road added by photorevision would be coded
            as follows:
                 170 0000 - obtained by photorevision
                 170 0209 - improved light duty
  
            b.  A boundary line added by photorevision would be coded
            as follows:
                 090 0000 - obtained by photorevision
 
            The photorevised code is not assigned to a node except
            when the node represents a photorevised feature on the
            map.  For example, a lake or pond, 0.030 inch or less in
            diameter with a drain attached, added by
            photorevision is digitized as a node and coded as follows:
                 050 0000 - obtained by photorevision
                 050 0200 - shoreline
                 050 0421 - lake or pond

            This code may also be used in conjunction with the best
            estimate of position and (or) classification code, when
            map features obtained by photorevision methods are printed
            in purple on 1:24,000- and 1:25,000-scale maps but are not
            labeled.  For example, a class 3 or 4 road that does not
            appear to be a part of the road network might be coded as
            follows:
                 200 0000 - obtained by photorevision
                 200 0214 - racetrack or drag strip
                 208 0000 - best estimate of position or classification
  
            Best estimate of position and (or) classification (XX8
            0000)
            The attribute code consisting of major code XX8, where XX
            are the two digits uniquely identifying the data category,
            and a minor code of zero indicates that the position and
            (or) classification of the feature is not sufficiently
            clear to warrant unqualified use of the attribute code
            assigned.

            Coincident feature (XX9 00YY)
            The attribute code having major code XX9, where XX are the
            two digits uniquely identifying the data category, is used
            to indicate that the digitized feature occupies the same
            position as a feature from another data category.  The
            second category is identified by the last two digits in
            the minor code.  YY are the first two digits of the major
            code of the second category.  For example:
                 309 0009 - land line coincident with boundary
                 099 0017 - boundary coincident with road
                 099 0002 - boundary coincident with watershed divide

            In most cases the lines where features are coincident are
            shown on the published map, however, land lines are
            omitted where they coincide with features of higher 
            order symbolization, such as civil boundaries, roads, 
            levees, or canals.

            These codes are included primarily as an aid in vertical
            integration of data from several categories.  Specific
            instructions applicable to a given category of data appear
            in the code descriptions for that category.

            Processing line (XX0 0299)
            The attribute code consisting of major code XX0, where XX
            are the two digits uniquely identifying the category, and
            a minor code of 0299, indicates that a digitized line has
            segmented the data within a file for processing.  For
            example:
                 050 0299 - Processing line code for hydrography
            This code is included primarily as an aid in the
            processing of large files that exceed the limitations of
            routines within the processing system (PROSYS).
  
  















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  (Current version containing all changes through 11/15/93)





  3.5            HYDROGRAPHY--MAJOR CODE 050

  3.5.1          General Principles
                 The purpose in digitizing hydrography is to collect
                 information about streams, bodies of water, wetlands,
                 coastal water, and water used for transportation and
                 related hydrographic features in a manner that permits the
                 extraction and derivation of data to suit the needs of the
                 data users.  This information is not collected for
                 specific hydrologic studies or for navigational
                 assistance.

                 One intention in collecting hydrography is to capture the
                 direction of the flow by theoretically looking downstream
                 and indicating right and left banks.  Where the flow
                 direction of a stream cannot be determined from the source
                 material, the adjoining quadrangles are examined to obtain
                 the information.  If the directional flow still cannot be
                 determined, the nodes and (or) banks are not coded to
                 indicate flow.

                 All double line streams are digitized as areas.  Double
                 line streams that join another double line stream or a
                 water body are closed by an arbitrary closure line.

                 The description of hydrographic features uses all of the
                 types of codes:  node, area, line, single-point, general
                 purpose, and descriptive.
  
                 All hydrographic features that have attribute codes
                 assigned are assumed to be perennial unless the attribute
                 code for "intermittent" is also assigned.

                 Hydrographic features do not carry attribute codes for
                 information that can be derived, such as intersections and
                 junctions.  This means that there will be unattributed
                 nodes, areas, and lines.

                 When an area feature, which can be identified by a code,
                 is subdivided by linear features or closure lines, each
                 resultant smaller area is identified by the appropriate
                 code.

                 The background land area is not assigned an attribute
                 code.  In some cases, land occurs as a brown area 0.030
                 inch in diameter or smaller.  This is digitized as a
                 degenerate line with the appropriate shoreline code.
 
  3.5.1.1        Hydrography Attribute Codes
                 The attribute codes used in digitizing hydrographic
                 information are listed in this section.  Instructions for
                 the use of the attribute codes are given in sections 3.5.2
                 through 3.5.8.

                    o  Node attribute codes
                             050 0001  Upper origin of stream
                             050 0002  Upper origin of stream at water body
                             050 0003  Sink, channel no longer evident
                             050 0004  Stream entering water body
                             050 0005  Stream exiting water body

                    o  Area attribute codes
                             000 0000  Outside area
                             050 0100  Alkali flat
                             050 0101  Reservoir
                             050 0102  Covered reservoir
                             050 0103  Glacier or permanent snow field
                             050 0104  Salt Evaporator
                             050 0105  Inundation area
                             050 0106  Fish hatchery or farm
                             050 0107  Industrial water impoundment
                             050 0108  Area to be submerged
                             050 0109  Sewage disposal pond or filtration plant
                             050 0110  Tailings pond or settling basin
                             050 0111  Marsh, wetland, swamp, or bog
                             050 0112  Mangrove area
                             050 0113  Rice field
                             050 0114  Cranberry bog
                             050 0115  Flats (tidal, mud, sand, or gravel)
                             050 0116  Bays, estuaries, gulfs, oceans, or seas
                             050 0117  Shoal
                             050 0118  Soda evaporator
                             050 0119  Duck pond
                             050 0120  Void area
                             050 0121  Obstruction area in water area
  
                    o  Line attribute codes
                             050 0200  Shoreline
                             050 0201  Manmade shoreline
                             050 0202  Closure line
                             050 0203  Indefinite shoreline
                             050 0204  Apparent limit
                             050 0205  Outline of a Carolina bay
                             050 0206  Danger curve
                             050 0207  Apparent shoreline
                             050 0208  Sounding datum
                             050 0209  Low-water line
                             050 0299  Processing line
  
                    o  Single-point attribute codes (degenerate lines)
                             050 0300  Spring
                             050 0301  Nonflowing well
                             050 0302  Flowing well
                             050 0303  Riser
                             050 0304  Geyser
                             050 0305  Windmill
                             050 0306  Cistern
  
                   o  General purpose attribute codes (apply to nodes,
                      areas, lines, or degenerate lines)
                             050 0400  Rapids
                             050 0401  Falls
                             050 0402  Gravel pit or quarry filled with water
                             050 0403  Gaging station
                             050 0404  Pumping station
                             050 0405  Water intake
                             050 0406  Dam or weir
                             050 0407  Canal lock or sluice gate
                             050 0408  Spillway
                             050 0409  Gate (flood, tidal, head, or check)
                             050 0410  Rock
                             050 0411  Crevasse
                             050 0412  Stream
                             050 0413  Braided stream
                             050 0414  Ditch or canal
                             050 0415  Aqueduct
                             050 0416  Flume
                             050 0417  Penstock
                             050 0418  Siphon
                             050 0419  Channel in water area
                             050 0420  Wash or ephemeral drain
                             050 0421  Lake or pond
                             050 0422  Coral reef
                             050 0423  Sand in open water
                             050 0424  Spoil area, dredged area, or dump area
                             050 0425  Fish ladders
                             050 0426  Holiday area

                    o  Descriptive attribute codes
                             050 0601  Underground
                             050 0602  Overpassing
                             050 0603  Elevated
                             050 0604  Tunnel
                             050 0605  Right bank
                             050 0606  Left bank
                             050 0607  Under construction
                             050 0608  Salt
                             050 0609  Unsurveyed
                             050 0610  Intermittent
                             050 0611  Abandoned or discontinued
                             050 0612  Submerged or sunken
                             050 0614  Dry
                             050 0615  Mineral or hot (sulphur, alkali, and so
                                       on)
                             050 0616  Navigable - transportation
                             050 0617  Underpassing
                             050 0618  Earthen construction
                             050 0619  Interpolated elevation
                             050 0621 - 0629  Decimal fractions of feet or
                                              meters

                    o  Parameter attribute codes
                             05N ----  Elevation of actual or interpolated 
                                       water surface
                                       N = 1 for whole feet
                                         = 2 for whole meters
                                         = 6 for whole feet below datum
                                         = 7 for whole meters below datum
                             Notes:  a.  Elevation value is flush right, four
                                         digits.
                                     b.  To express elevations in decimal feet 
                                         or meters, use the above parameter 
                                         codes in conjunction with attribute
                                         codes 050 0621 through 050 0629.
                                     c.  Elevations exceeding 9,999 feet 
                                         must be expressed in meters.


                             055 ----  River mile, value in four spaces, flush
                                       right
                             050 0000  Photorevised feature
                             058 0000  Best estimate of classification or
                                       position
                             059 00--  Coincident feature

  3.5.2          Node Attribute Codes
                 The primary purpose of the node attribute codes is to
                 assist in determining the direction of water flow.  In
                 assigning the node codes, the term "water body" refers to
                 any areal feature digitized in the hydrography category. 
                 These codes apply to nodes found at the terminus of a
                 given single-line stream segment.  Nodes are not coded at
                 connecting points where lines coded left and right bank
                 intersect other left and right bank lines.  Nodes are not
                 coded where lines coded left and right bank connect lines
                 bounding water bodies.  Also nodes are not coded in places
                 where direction of flow cannot be determined.

                 050 0001   Upper origin of stream
                            This code identifies a node placed at the 
                            true beginning of a stream, where it is 
                            first shown. It is not used to mark stream 
                            junctures, even though the name of the 
                            stream changes, or to mark streams that 
                            exit from a water body.

                 050 0002   Upper origin of stream at water body
                            This code identifies a node placed where a 
                            stream originates either within the limits 
                            of or at the point of exit from a water body. 
                            It is not used to identify any subsequent 
                            exits from water bodies further downstream.

                 050 0003   Sink
                            A sink is the definite point where a stream flows
                            underground, shown by symbols 407(A), 141.8(B),
                            541.12(C), or 2202.04(D).  This code is used to
                            identify a node placed at the point of
                            disappearance.  This code is not used to identify
                            points where streams enter manmade features, such
                            as aqueducts or siphons, or where streams enter
                            and subsequently exit water bodies.

                 050 0004   Stream entering water body
                            This code identifies a node placed at the
                            terminus of a single-line stream segment where it
                            ends within the limits of or at the perimeter of
                            a water body.

                 050 0005   Stream exiting water body
                            This code identifies a node placed at the
                            terminus of a single-line stream segment where it
                            begins within the limits of or at the perimeter
                            of a water body, other than at an upper origin of
                            a stream.

3.5.3          Area Attribute Codes
               000 0000     Outside area
                            This code is described in section 3.3.3.

               050 0100     Alkali flat
                            This code identifies a point placed within an
                            area shown by symbols 450(A), 141.16(B),
                            541.28(C), or 2203.08(D) and labeled.

               050 0101     Reservoir
                            This code identifies an area point placed in a
                            reservoir shown by symbols 179, 413 (A); 112.6,
                            141.12, 141.13, 145.2 (B); 512.61, 541.24 (C); or
                            2203.09(D) that is labeled or named as a
                            reservoir.  Use code 050 0200 for identification
                            of natural shoreline around symbols 413, 141.12,
                            141.13,  or 2203.09, and code 050 0201 for
                            manmade shoreline around symbols 179 or 145.2. 
                            If the symbol is 0.030 inch or less in diameter,
                            digitize as a degenerate line or node and add the
                            shoreline code.  This code is not used to
                            identify features related to sewage treatment,
                            fish farming, or water filtration.

               050 0102     Covered reservoir
                            This code identifies a point placed in a
                            reservoir area shown by symbol 180(A); 512.62,
                            545.6 (C); or 2106.08(D) and named or labeled as
                            a reservoir.  If the symbol is 0.030 inch or less
                            in diameter, digitize as a degenerate line or
                            node and add the shoreline code.  Use code 050
                            0201 for identification of manmade shoreline of
                            this feature.  This code does not apply to
                            1:100,000-scale maps.
               050 0103     Glacier or snowfield
                            This code identifies a point placed in an area
                            depicted by symbols 428, 429, 430 (A);  141.27,
                            141.28 (B); 541.43 through 541.45 (C); or
                            2205.04(D).  Because the symbols vary because of
                            the contouring, which is not pertinent to the
                            hydrographic category, the same code is applied to 
                            all three symbols.  Any areas where the glacial
                            moraine pattern overlaps a glacier is coded
                            coincident with the Non-Vegetative Features
                            category (059 0008).  The outline of the area is
                            not given an attribute code.

               050 0104     Salt evaporator 
                            This code identifies the points placed in each
                            section of areas shown by symbols 439(A),
                            141.15(B), 541.27(C), or 2205.10(D) and labeled. 
                            The pattern of ditches is digitized and coded
                            (see code 050 0414).

               050 0105     Inundation area
                            This code identifies a point placed in the area of
                            land between the normal operating level and the
                            high water line in reservoirs or lakes impounded
                            by dams.  This area is shown by symbols 448(A),
                            141.38(B), 541.56 or 546.1 (C).  Generally, code
                            the outer line as symbolized.  However, on older
                            1:24,000-scale quads, if the outer line is shown
                            as an indefinite shoreline and the inundation area 
                            is in a non-coastal area, then code the outer line
                            as intermittent shoreline (see code 050 0203 for
                            further explanation).  If an area subject to
                            controlled inundation is symbolized with an
                            elevation value on the shoreline defining the
                            area, the elevation parameter code is added.  Use
                            code 050 0412 or 050 0414 for identification of
                            drainage pattern in the area.

               050 0106     Fish hatchery, fish farm, or fish pond
                            This code identifies a point placed in any area
                            shown by symbols 179(A); 112.6, 145.2 (B); 512.61,
                            545.5 (C); or 2205.11(D) and labeled.  The label 
                            may vary to indicate the species or the 
                            controlling agency.  The outline is coded 
                            050 0201 if shown in black and 050 0200 if 
                            shown in blue.  The major ditches are coded 
                            050 0414 if shown in blue or 050 0201
                            if shown in black.  The fish pond, unique to maps
                            of Hawaii, may or may not be labeled.  If the
                            outline is shown by a solid black line, the
                            outline is coded 050 0201; if shown by a dashed
                            black line also use code 050 0611 (abandoned) for
                            the area.  In all cases, each section has a coded
                            area point placed in it.

               050 0107     Industrial water impoundment
                            This code identifies a point placed in an area
                            that is shown by symbols 410(A), 141.12(B),
                            541.23(C), or 2203.03(D), and carries a label
                            that indicates the water is collected for
                            industrial use, such as "industrial waste pond"
                            or "cooling pond."  This does not include the
                            features related to sewage treatment, fish
                            farming, water filtration, or mining.
               050 0108     Area to be submerged
                            This code identifies a point placed in an area
                            shown by symbols 702(A), 141.39(B), 541.57, 547.2
                            (C), or 2203.07(D).  The symbol depicts the
                            expected normal pool elevation.  Generally, code
                            the outer line as symbolized.  However, on older
                            1:24,000-scale quads, if the outer line is shown
                            as an indefinite shoreline, then code the outer
                            line as shoreline (see code 050 0203 for further
                            explanation).  If an elevation value is shown on
                            the shoreline defining the area, the elevation
                            parameter code is added.  Features within the
                            area are double coded (i.e., stream (050 0412),
                            area to be submerged (050 0108)).  This area is
                            used when a dam is under construction and the
                            limits of the intended reservoir are known.               050 0109     Sewage disposal pond or filtration plant
                            This code identifies a point placed in any area
                            that relates to the treatment of sewage.  These
                            features may be shown by symbols 410(A); 112.5,
                            141.12 (B); 512.59, 547.3 (C); or 2203.03,
                            2205.12, 2205.13 (D).  The features are labeled in
                            various ways such as "sewage disposal pond" or
                            "filtration bed."  This code is also applied to
                            ponds that are unlabeled but are shown by symbols
                            700(A), 147.3(B), or 2106.07(D) and are located
                            adjacent to a labeled sewage disposal plant.  When
                            this symbol is 0.030 inch in diameter, digitize as
                            a degenerate line.  Use code 050 0200 for blue
                            outlines or code 050 0201 for black outlines.  On
                            1:100,000-scale maps the sewage disposal plant is
                            digitized by placing the area point in symbol
                            147.3(B).  The outline shown by symbol 112.5(B) is
                            coded with 050 0201.

               050 0110     Tailings pond or settling basin
                            This code identifies a point placed in an area
                            shown by symbols 323(A); 132.16, 134.2 (B);
                            532.22, 538.1 (C); or 2112.05(D); and labeled
                            "tailings pond" or "settling basin." Use code 050
                            0204 for outline of pond when it is limited by the
                            contour.  Do not code the outline otherwise.

               050 0111     Marsh, wetland, swamp, or bog
                            This code identifies a point placed in any area
                            shown by symbols 431(A), 143.1(B), 543.1(C), or
                            2205.05(D).  If the area being digitized has no
                            definite outline shown, the edge of the pattern is
                            followed to delimit the area (see code 050 0204).

                            Any portion of a wetland that is overprinted with
                            blue as in symbols 433(A), 141.35, 143.2 (B),
                            543.2(C), or 2205.06(D), is digitized as a
                            separate area with the code assigned to indicate
                            that it  is  a marsh (050 0111)  and  is 
                            submerged (050 0612).    Any  portion  of  a 
                            wetland that is overprinted with green tint 
                            to indicate it is wooded, as in symbols 
                            432(A) or 543.03(B), is digitized as a 
                            separate area with the code to
                            indicate that it is a swamp (050 0111) coincident
                            with Vegetative Surface Cover (059 0007).  Any
                            portion of a wetland that is overprinted with
                            green\blue to indicate it is submerged wooded
                            swamp, as in symbols 543.4(B) or 141.37(B), is
                            digitized as a separate area with the code
                            assigned to indicate that it is a marsh (050
                            0111), submerged (050 0612), and coincident with
                            Vegetative Surface Cover (059 0007).  The code
                            059 0007 does not apply to 1:100,000-scale maps
                            (see figure 3-1).  Any streams shown in wetland
                            areas are digitized as separate features (see 
                            code 050 0412).

               050 0112     Mangrove area
                            This code identifies a point placed in an area
                            shown by symbols 437(A); 144.1, 152.4 (B); 544.1,
                            552.4 (C); or 2205.08, 2402.06 (D).  If the
                            outline of the area is not clearly defined, the
                            edge of the pattern is followed to delimit the
                            area (see code 050 0204).

               050 0113     Rice field
                            This code identifies a point placed in an area
                            shown by symbols 436(A), 548.1(C), or 2205.07(D).

                            If the outline of the area is not clearly defined,
                            the edge of the pattern is followed to delimit the
                            area (see code 050 0204).  This code does not
                            apply to 1:100,000-scale maps.

























                                            Area      Parameter
     Area     Feature                     attribute   attribute
                                            code        code

      1       Woods                       --- ----       ----
      2       Submerged woods             050 0421**   059 0007*
                (wooded lake)
      3       Submerged wooded swamp      050 0111,    059 0007*
                                          050 0612**
      4       Wooded swamp                050 0111     059 0007*
      5       Swamp                       050 0111       ----
      6       Submerged swamp             050 0111,      ----
                                          050 0612**     ----
      7       Lake                        050 0421**     ----

    * This code does not apply to 1:100,000-scale maps.
   ** If area meets minimum size criteria, add interpolated elevation
      attribute code and appropriate elevation value.


                             Figure 3-1
      Attribute and parameter coding for hydrography coincident with
                      vegetative surface cover



               050 0114     Cranberry bog
                            This code identifies a point placed in each
                            section of an area shown by symbols 438(A),
                            141.36(B), 541.49(C), or 2205.09(D) and labeled
                            "cranberry bog."  There may be several cranberry
                            bogs in a group with one label "cranberry bogs." 
                            Code the outer line intermittent shoreline (see
                            codes 050 0610 or 050 0200).  The ditch pattern is
                            digitized as shown and coded intermittent ditch
                            (see codes 050 0610 or 050 0414).

               050 0115     Flats (tidal, mud, sand, or gravel)
                            This code identifies a number of features that
                            fall into the general category of flats (e.g.,
                            foreshore flats, areas inside of rock reefs, and
                            the area between the shoreline and sounding datum
                            line on topographic-bathymetric editions).  These
                            features are shown by symbols 232(A), 316(A),
                            517.1(C), or 2113.01(D).  On topographic-
                            bathymetric editions, flats are shown by 135.7(B)
                            or 535.10(C).  The area is usually labeled by
                            type, that is, mud, tidal, gravel, sand, or shell. 
                            Do not include in this classification features
                            such as sand dunes, sand in open water (see 050
                            0423), or beach areas on dry land.  Use code 050
                            0204 for the outline of an area that is not
                            otherwise symbolized with a shoreline feature.

               050 0116     Bays, estuaries, gulfs, oceans, or seas
                            This code is used to identify a seaward area of
                            water.  The inland extent is defined at the place
                            where a double-line stream reaches a width of l
                            nautical mile (6,080 feet) with no further
                            constrictions, if the conformation of the land and
                            water do not otherwise make the division obvious.

                            A closure line is placed to separate the bay,
                            estuary, gulf, ocean, or sea from a double-line
                            stream (050 0202).               050 0117     Shoal
                            This code identifies a shoal area shown by symbols
                            243(A), or 512.142(C) and labeled "Shoal."  This
                            code does not apply to 1:100,000-scale maps.

               050 0118     Soda evaporator
                            This code identifies an area shown by symbols
                            439(A), 141.15(B), 541.27(C), or 2205.10(D) and
                            labeled.  On the 1:100,000-scale maps, symbol
                            141.15(B) with a blue dot or blue dash fill is
                            used.  The pattern of ditches is digitized and
                            coded (see code 050 0414).

               050 0119     Duck Pond
                            This code identifies an area labeled "Duck Pond."
                            This feature is shown by symbols 141.17, 146.2 (B)
                            or 541.29, 546.2 (C).  Generally, code the outer
                            line as symbolized.  However, on older 1:24,000-
                            scale quads, if the outer line is shown as an
                            indefinite shoreline, then code the outer line as
                            intermittent shoreline (see code 050 0203 for
                            further explanation).  The ditch pattern is
                            digitized as shown and coded intermittent ditch
                            (see codes 050 0610 or 050 0414).

               050 0120     Void area
                            This code identifies an area on the source where
                            hydrographic data do not exist or are interrupted
                            because of replacement by imagery or a pattern
                            from another category.  A void area is also found
                            beyond the national boundary to distinguish it
                            from the background area.  Where appropriate, the
                            perimeter of the void area, usually a closure
                            line, is coded as coincident with the category
                            whose pattern defines the hydrographic void area.
                            The closure line that defines the void area beyond
                            the national boundary is coded as coincident with
                            the Boundaries category (059 0009).

               050 0121     Obstruction area in water area
                            This code identifies an obstruction area in a
                            water area shown with a double dashed line and
                            labeled "Pipelines obstruction area," "Cable
                            area," "Pipeline area," or "Cable-Pipeline area."
                            By definition, this denotes water area and
                            therefore the area is not double-coded.  Arbitrary
                            closure lines are required to complete the
                            definition of an open-ended area.  The limits of
                            the area are not otherwise coded.3.5.4          Line Attribute Codes
               050 0200     Shoreline
                            This code identifies a natural shoreline shown by
                            symbols 400(A), 141.1(B), 541.1(C), or 2203.01(D)
                            and islands larger than 0.030 inch in diameter. 
                            The shoreline of an intermittent water body is
                            coded 050 0200 and 050 0610 (intermittent).  This
                            code is also used to define the shorelines of
                            double-line streams and ditches when the direction
                            of flow cannot be determined (when direction of
                            flow can be accurately determined, use codes 050
                            0605 and 0606).  This code is also used to
                            identify the shoreline of islands, lakes, and
                            reservoirs that are digitized as degenerate lines.

               050 0201     Manmade shoreline
                            This code identifies the shoreline around or along
                            a body of water to indicate that the shoreline is
                            shown by a black outline.  Where the shoreline is
                            broken by a single-line pier, wharf, or jetty, the
                            single-line feature is not digitized as part of
                            the manmade shoreline.  This code is also used to
                            identify the shoreline of islands, lakes, and
                            reservoirs that are digitized as degenerate lines.

               050 0202     Closure line
                            This code identifies a line segment digitized to
                            form the closure of an areal feature whose outline
                            is not explicitly symbolized.  It is used, for
                            example, as a line between hydrographic areas to
                            retain the separate identity of each, such as
                            where a double-line stream enters a lake or bay. 
                            This code also identifies a line segment used to
                            close gaps in streams where the symbol has been
                            broken.  When this code is used as an arbitrary
                            extension, the primary code should be used also. 
                            A closure line is used to define the extent of a
                            void area that is not otherwise symbolized.

               050 0203     Indefinite shoreline
                            This code identifies a line shown by symbols 401,
                            415 (A); 141.3(B); 541.3(C); or 2203.02(D); which
                            indicates that the shoreline cannot be definitely
                            established.  Note that on 1:24,000-scale quads
                            compiled using older Part 6 symbology an
                            indefinite shoreline was shown around hydrographic
                            features that are now shown with an intermittent
                            shoreline (intermittent ponds, dry lakes, duck
                            ponds, inundation areas in non-coastal areas) or
                            a shoreline (area to be submerged).  On these
                            quads, code these lines as intermittent shoreline
                            or shoreline, not indefinite shoreline.

               050 0204     Apparent limit
                            This code identifies a line digitized around
                            various fea-tures represented by an areal pattern
                            when a definite out-line does not exist.  The edge
                            of the pattern (such as marsh or wash) is followed
                            as closely as possible and carries this code to
                            indicate the arbitrary nature of the line.

               050 0205     Outline of a Carolina bay
                            This code identifies a line shown by symbols
                            401(A), 141.7(B), 541.17(C), or 2205.19(D).  The
                            feature is outlined by a dashed blue line and is
                            noted on the map collar.  Any other hydrologic
                            feature within the area of a Carolina bay, such as
                            marsh, lake, or ditch, is digitized as a separate
                            feature.  If a bay outline is a complete and
                            closed ellipse, the interior area does not have an
                            attribute code unless it is a hydrologic feature
                            in its own right.

               050 0206     Danger curve
                            This code identifies a line shown by symbol
                            244(A), which represents the limit of an area
                            considered to be dangerous for navigation.

               050 0207     Apparent shoreline
                            This code identifies a line shown by symbols
                            141.2(B) or 541.2(C), which represents a coastal
                            shoreline in areas of marsh, grass, mangrove, or
                            other similar marine vegetation.  This symbol is
                            shown at the outer edge of vegetation, instead of
                            the mean high-water line, and is used with
                            topographic-bathymetric maps only.

               050 0208     Sounding datum
                            This code identifies a line shown by symbols
                            141.40(B) and 541.59(C), which represents the
                            starting elevation (0) for bathymetric contours
                            and is the mean lower low-water line.  This
                            symbol is found on topographic-bathymetric maps
                            only.

               050 0209     Low-water line
                            In areas where the shoreline is undetermined or
                            varies because of meteorological or other
                            conditions, double-line streams are shown with
                            the following symbols (starting onshore): a
                            dashed (indefinite) shoreline, "area subject to
                            inundation" fill, a line of small dashes (the
                            marsh outline symbol) indicating mean low water
                            or mean lower low water, and then the blue fill. 
                            This code identifies a line shown by symbols
                            541.47(C) and 546.1(C), which represents the mean
                            low-water or mean lower low-water line.

               050 0299     Processing line
                            Some routines in the processing software (PROSYS)
                            have limitations on the number of lines, nodes,
                            or areas that can be processed.  For example, an
                            area may be associated with no more than 4,751
                            lines.  This code describes a line or lines
                            digitized to segment the data within a file to
                            create more background areas, thereby enabling
                            large files to be processed.

  3.5.5        Single-Point Attribute Codes
               050 0300     Spring
                            This code identifies a point placed in the center
                            of the circular portion of a feature shown by
                            symbols 427(A), 141.25(B), 541.40(C), or
                            2205.03(D) and labeled.  When the center of the
                            circular portion of the spring symbol does not
                            fall directly on a linear feature in this
                            overlay, it is digitized as a degenerate line. 
                            However, when the center of the circular portion
                            of the spring symbol occurs directly on a linear
                            feature, such as a stream, it is digitized as a
                            node.  In this case the tail of the spring is
                            ignored and the node is connected to the stream
                            element by digitizing a line following the
                            general alignment of the stream on the source,
                            and this line is coded consistent with the
                            stream.  In the case where the spring is the
                            origin of a single-line stream, apply the code
                            for spring to the node along with 050 0001.

               050 0301     Nonflowing well
                            This code identifies a point placed on a feature
                            shown by symbols 426(A), 141.26(B), 541.39(C), or
                            2205.02(D) and labeled.  In areas where wells are
                            numerous, they may not all be labeled but are
                            still digitized.  This code may also be used on
                            a node when the well symbol occurs directly on a
                            line that is being digitized in the hydrographic
                            overlay.  A well is assumed to be nonflowing when
                            labeled only as "Well."

               050 0302     Flowing well
                            This code identifies a point placed on a feature
                            shown by symbols 426(A), 141.26(B), 541.39(C), or
                            2205.02(D) and labeled "Flowing well".  This code
                            may also be used on a node when the well symbol
                            occurs directly on a line that is being digitized
                            in the hydrographic overlay.

               050 0303     Riser
                            This code identifies a point placed on a feature
                            that is shown by the located object symbol 198(A)
                            or 2111.03(D) and labeled "riser."  A riser is a
                            vertical overflow pipe controlling the water
                            level in a reservoir.

               050 0304     Geyser or vent
                            This code identifies a point placed on a special
                            type of spring that ejects hot water or steam
                            periodically.  This includes gas vents, mud pots,
                            fumaroles, and steam vents.  It is shown by
                            symbols 427(A), 141.26(B), 541.39(C), or
                            2205.03(D) and labeled.

               050 0305     Windmill
                            This code identifies a point placed on a well
                            shown by symbols 199(A), 112.3(B), 512.69(C), or
                            2111.04(D).  If the label indicates the well is
                            dry or salt, use codes 050 0614 or 050 0608 in
                            addition.

               050 0306     Cistern
                            This code identifies a point placed on a feature
                            shown by symbols 426(A), 141.26(B), 541.39(C), or
                            2205.02(D) and labeled "cistern."  This code may
                            also be used on a node when the symbol occurs
                            directly on a line that is being digitized in the
                            hydrography overlay.

  3.5.6        General Purpose Attribute Codes
               050 0400     Rapids
                            This code identifies rapids that are digitized as
                            a node, area, or line, depending on the symbol
                            treatment on the source.  When rapids are shown
                            by double ticks across a single-line stream as in
                            symbols 443(A), 141.32(B), 541.54(C), or
                            2205.17(D), digitize a node between and
                            equidistant from the points where the ticks
                            intersect the stream.  When shown by several
                            ticks across a single-line stream, digitize a
                            node at the beginning and ending points where the
                            ticks intersect the stream and apply this code to
                            the section of line between the nodes.  If the
                            rapids are shown by double ticks across a narrow
                            double-line stream, as in symbols 141.32(B), or
                            541.54(C), digitize a line from bank to bank that
                            is between and equidistant from the two ticks. 
                            In the case where the rapids are shown by a
                            pattern of ticks as in symbols 442(A), 141.31(B),
                            541.53(C), or 2205.16(D), then digitize an area
                            point in the rapids and identify it with this
                            code.  The limit is digitized with a closure line
                            (050 0202) from bank to bank along the upstream
                            and downstream edges of the ticks.  The rapids
                            area is implicitly part of the stream and does
                            not need to be coded as "stream."

               050 0401     Falls
                            This code identifies a node placed where the tick
                            mark in symbols 441(A), 141.30(B), 541.52(C), or
                            2205.15(D) intersects a single-line stream to
                            show a small falls.  It also identifies a
                            digitized line that follows the upstream edge of
                            symbols 440(A), 141.29(B), 541.51(C), or
                            2205.14(D) to depict a large falls on a
                            double-line stream.  In the case of a tick mark
                            across a narrow double-line stream as is shown in
                            symbols 141.30(B) or 541.52(C), digitize a line
                            along the tick and identify it with this code.

               050 0402     Gravel pit or quarry filled with water
                            This code identifies a body of water that has
                            formed naturally in a manmade excavation.  It is
                            labeled as gravel pit or quarry.  If the feature
                            is 0.030 inches or less in diameter, it is
                            digitized as a degenerate line.  If it is greater
                            than 0.030 inch in diameter, it is digitized as an
                            area.

               050 0403     Gaging station
                            This code identifies a point placed on symbols
                            200(A), 112.45(B), 512.113(C), or 2111.05(D).  If
                            the center of the gaging station symbol occurs
                            directly on a line, such as a single-line stream
                            or bank of a double-line stream, it is digitized
                            as a node on that line.  If the center of the
                            symbol is placed off the line, digitize as a
                            degenerate line.

               050 0404     Pumping station
                            This code identifies a point placed on symbols
                            201(A), 163(A), 112.7(B), or 2111.06(D) and
                            labeled.  If the feature is shown with the minimum
                            size building symbol, 163(A), and occurs directly
                            on a digitized line, it is coded as a node.  If it
                            is separate from the line and shown with the
                            minimum size building symbol, 163(A), it is
                            digitized as a degenerate line. If the feature is
                            shown to scale, 165(A), it is digitized as an
                            area.

               050 0405     Water intake
                            This code identifies a point placed on a labeled
                            water intake shown by symbols 198(A) or
                            2111.03(D).  If the symbol is on a digitized line,
                            it is digitized as a node.  If the symbol is
                            separate from the line, it is digitized as a
                            degenerate line.  This code does not apply to
                            1:100,000- scale maps.

               050 0406     Dam or weir
                            This code identifies a feature shown by symbols
                            152, 153, 313 (A); 112.63, 132.14 (B); 512.34,
                            512.35, 532.9 (C); or 2108.01, 2108.02, 2302.08
                            (D).  The feature may be labeled or named.  A weir
                            may be labeled "diversion weir".  The code is used
                            as a line code when the dam is shown by a line. 
                            When the dam is shown by contouring, digitize the
                            straight segment of the shoreline of the impounded
                            water, parallel to the contouring, and code as
                            dam.  In general, a single-line dam is digitized
                            uniquely, and not double coded as shoreline. If
                            the dam is carrying a road as in symbols 155(A),
                            112.65(B), 511.20, 512.37 (C), or 2108.04(D),
                            digitize a centerline equidistant from the two
                            road casings and use code 059 0017 as well to
                            indicate the coincidence.  The code is used as an
                            area code when the dam is a large structure
                            depicted to scale.  The outer limits of the dam
                            generally are unattributed, except the edge
                            defining a shoreline, which is coded with the
                            appropriate shoreline code.  The radiating lines
                            within symbol 153(A) are not digitized.  See code
                            050 0407 for treatment of lock as in symbols
                            154(A), 112.64(B), 512.36(C), or 2108.03(D).  If
                            the dam is of earthen construction also use code
                            050 0618.

               050 0407     Canal lock or sluice gate
                            This code identifies canal locks or sluice gates
                            shown by symbols 160, 161, 154 (A); 112.66(B);
                            512.36, 512.38 (C); or 2108.08, 2108.09, 2108.03
                            (D).  It is used as a node or line code depending
                            on the size of the feature.  Symbols 160(A) or
                            2108.08(D) are digitized as nodes on the
                            single-line stream.  Symbols 161(A) or 2108.09(D)
                            are digitized as lines across a double-line
                            stream.  The lock
                            symbol within symbols 154(A) or 2108.03(D) is
                            digitized as a node on the dam line if shown at
                            symbol size (0.075 by 0.033 inch). If digitized
                            to scale and larger than the symbol, the outline
                            of the lock is digitized and coded.  Some major
                            rivers have extensive structures shown to scale
                            for which the lock code is used on the enclosed
                            areas of the structures as well as any linear
                            extent.  The enclosed water areas are not coded
                            as stream because that information is implied by
                            the feature.

               050 0408     Spillway
                            This code identifies a spillway, which is shown
                            on a map in various ways.  The spillway is
                            digitized as a node, area, line, or degenerate
                            line according to the size of the feature.  If it
                            is shown by a small circle or dot, it is
                            digitized as a degenerate line.  If the feature
                            is shown by drainage lines, perennial or
                            intermittent, it is digitized as a line.  If the
                            spillway is indicated by an arrangement of
                            contour lines or a black box, it is digitized as
                            an area.  If a spillway is represented as an
                            integral part of the dam, this code and an
                            elevation value (if applicable) are assigned to
                            a node on the digitized line of the dam.  Some
                            judgment is required to correctly digitize the
                            spillway, as the feature is not always labeled. 
                            The label "Spillway elevation NNNN" placed in the
                            impounded water area is sometimes the only
                            reference to the feature.  If the feature itself
                            is represented by a label only, this code and the
                            elevation value are assigned to a node placed on
                            the digitized shoreline near the label.

               050 0409     Gate (flood, tidal, head, or check)
                            This code identifies a variety of labeled
                            features used to control or divert the flow of
                            water.  These features are shown by a tick or
                            black line.  If shown by a tick on a
                            single-line stream, a node is digitized and
                            coded.  If shown by a line on a double-line
                            stream, the line is digitized and coded.

               050 0410     Rock
                            This code identifies a rock or group of rocks
                            shown by symbols 236, 237, 238, 246 (A); 112.97,
                            112.98, 112.99 (B); 512.136 through 512.138,
                            512.160 (C); or 2113.03, 2113.04 (D).  A rock
                            shown by symbols 236, 237 (A); 112.97(B);
                            512.136, 512.137 (C); or 2113.03(D) is digitized
                            as a degenerate line.  A group of rocks less than
                            0.030 inch diameter is also digitized as a
                            degenerate line.  If the rocks are shown by
                            symbols 238(A), 112.98(B), 512.138(C), or
                            2113.04(D), the outline is digitized but not
                            coded; a point is placed in the area and coded. 
                            A sunken rock shown by symbols 246(A), 112.99(B),
                            or 512.160(C) is digitized as a degenerate line
                            and is assigned this code as well as code 050
                            0612 (sunken).

               050 0411     Crevasse (glacial)
                            This code identifies crevasse lines and crevasse
                            areas depicted by symbol 453(A).  If the crevasse
                            area contains less than four lines, the
                            individual lines are digitized.  Crevasse areas
                            that contain four or more lines are digitized as
                            an area.  The edge of the crevasse pattern is
                            digitized as an apparent limit (see code 050
                            0204).  This code does not apply to
                            1:100,000-scale maps.

               050 0412     Stream
                            This code identifies all naturally flowing water
                            except braided streams (see code 050 0413). 
                            Streams are shown by symbols 402, 403, 405, 406,
                            408 (A); 141.4, 141.5, 141.6 (B); 541.4, 541.5,
                            541.7, 541.8, 541.10, 541.11 (C); or 2202.01,
                            2202.02, 2202.05 (D).  Single-line streams are
                            digitized as lines.  Double-line streams are
                            digitized as areas.  The limits of the
                            double-line stream area are formed by the left
                            and right banks (see codes 050 0605 and 050
                            0606), by a closure line (code 050 0202) to
                            separate the stream from a hydrographic area that
                            it enters, or by the neatline.  The course of a
                            submerged stream in an impounded water area is
                            digitized as a separate area with the stream code
                            and the descriptive code for submerged (code 050
                            0612).  The dashed blue lines are generally
                            digitized as unattributed lines. Use the
                            appropriate descriptive codes for streams that
                            are intermittent or unsurveyed.  In some cases an
                            appropriately symbolized natural stream course
                            will carry a ditch label; however, do not code as
                            ditch.

               050 0413     Braided stream
                            This code identifies braided streams that are
                            shown by symbols 404(A), 541.6, 541.9 (C), or
                            2202.03(D).  A braided stream is a special case
                            where the stream subdivides into interlacing
                            channels.  In map compilation, where possible,
                            the actual channels are shown.  However, if the
                            channels are extremely complex or obscured by
                            vegetation, the outer limit is scribed accurately
                            and the inner channels are represented by a
                            conventional pattern.  The use of pattern versus
                            actual channel is not noted on the map. 
                            Therefore, the braided portion of a stream is
                            digitized as an area that carries this code.  The
                            outer limits are digitized and carry left and
                            right bank codes (see codes 050 0605 and 050
                            0606).  The braided area is separated from a
                            double-line stream by a closure line (code 050
                            0202) and from a single-line stream by nodes (see
                            codes 050 0004 and 050 0005).

               050 0414     Ditch or canal
                            This code identifies any manmade, flowing water
                            feature used for irrigation, drainage, or
                            transportation shown by symbols 416 through 422
                            (A); 141.19, 141.20 (B); 541.31 through 541.33
                            (C); or 2204.01 through 2204.06 (D).  These may be
                            labeled or unlabeled.  Manmade water courses, of
                            various shapes, are included in this code, even if
                            not labeled.  If an obviously natural stream
                            course carries a ditch label, do not use this
                            code.  Some natural streams have portions that
                            appear to have been realigned by man.  If the
                            artificial portion of a natural stream is not
                            identified by a label or name change, do not use
                            this code.  The banks of double-line ditches and
                            the points of origin or where single-line canals
                            or ditches join water bodies are coded and
                            digitized in the same way as they are for streams
                            when the direction of flow can be determined. 
                            Navigable canals used for transportation have an
                            additional code added to preserve this information
                            (code 050 0616). Use additional descriptive codes
                            to identify canals that are abandoned,
                            intermittent, and so on.

               050 0415     Aqueduct
                            This code identifies features represented by
                            symbols 418, 419, 421, 423, 424, 425 (A); 141.19
                            through 141.23 (B); 541.31 through 541.36 (C); or
                            2204.03, 2204.04, 2204.06 through 2204.09 (D),
                            which are labeled "Aqueduct." Single-line
                            aqueducts are digitized as lines.  Double-line
                            aqueducts are digitized as areas.  The banks and
                            inter-sections of aqueducts with water bodies are
                            digitized and coded in the same manner as streams. 
                            An aqueduct that goes into an underground water
                            tunnel is shown by symbols 424(A), 141.23(B),
                            541.35(C), or 2204.08(D) regardless of size. 
                            Therefore, the portion of the aqueduct that is in
                            the tunnel is digitized as a line and carries the
                            code for tunnel
                            (050 0604) in addition to the aqueduct code. 
                            This code combination is also used for a feature
                            shown by symbol 424 but labeled water tunnel. Use
                            additional descriptive codes to identify
                            aqueducts that are abandoned, elevated, or
                            underground.

               050 0416     Flume
                            This code identifies features that are shown by
                            symbols 418, 419, 421, 423, 425 (A); 141.19
                            through 141.22 (B); 541.31 through 541.34, 541.36
                            (C); or 2204.03, 2204.04, 2204.06, 2204.07,
                            2204.09 (D) and labeled "Flume."  A flume is an
                            artificial open inclined channel that conveys
                            water for a special purpose and is frequently an
                            elevated feature.  A single-line flume is
                            digitized as a line.  A double-line flume is
                            digitized as an area.  The banks and the points
                            where flumes intersect water bodies are coded and
                            digitized in the same manner as streams.  Use
                            additional descriptive codes to describe flumes
                            that are abandoned or elevated.

               050 0417     Penstock
                            This code identifies a feature that is shown by
                            symbols 423, 425 (A); 141.21(B); 541.34, 541.36
                            (C); or 2204.07, 2204.09 (D) and labeled
                            "Penstock."  A penstock is an underground or
                            exposed pipe conveying water from a canal or a
                            dam to a hydroelectric plant.  It is usually
                            shown as a single-line feature, that is digitized
                            as a line.  The penstock may be carried
                            underground in an aqueduct tunnel, symbols
                            424(A), 141.23(B), or 2204.08(D), in which case
                            the single line is digitized and carries the
                            additional code for tunnel (050 0604).  In the
                            event that a penstock is shown as a double-line
                            feature in itself, it is digitized as an area. 
                            The banks and intersections with water bodies are
                            coded and digitized in the same manner as
                            streams.

               050 0418     Siphon
                            This code identifies features shown by symbols
                            452(A), 141.21(B), 541.41(C), or 2205.18(D).  A
                            siphon is a pipe conveying water to another
                            level, either over or under an obstruction.  On
                            1:24,000-scale maps, the dashes in the symbol may
                            be omitted on siphons less than 200 feet long and
                            a wing tick or break in the underpassing symbol
                            used instead.  On 1:100,000-scale maps a siphon
                            is labeled.  A single-line siphon is digitized as
                            a line.  A double-line siphon is digitized as an
                            area.  The limits of the area are unattributed. 
                            Use the code to indicate overpassing (050 0602)
                            or underpassing (050 0617) on the portion of the
                            siphon that crosses the obstruction.  The code
                            for overpassing is used if the relationship of
                            the features is not clear on the source material.

               050 0419     Channel in water area
                            This code identifies a feature shown by symbols
                            444(A); 112.94, 141.9, 141.34 (B); or 512.154
                            through 512.156, 541.15, 541.16 (C).  A channel
                            in a water area shown with a double line is
                            digitized as an area feature.  By definition,
                            this code denotes water area and therefore the
                            area is not  double coded.  Arbitrary closure
                            lines are normally required to complete the
                            definition of an open-ended channel.  The limits
                            of the area are not otherwise coded.  This code
                            does not apply to submerged river courses in
                            inundated areas.  Use this code to identify an
                            airboat trail, canoe trail, or wilderness
                            waterway shown by one of the symbols listed
                            above.  See code 050 0616 for the application of
                            the "navigable" descriptive code to channels.

               050 0420     Wash or ephemeral drain
                            This code identifies features shown by symbols
                            317, 409 (A); 134.1, 141.6 (B); 534.3, 541.13
                            (C); or 2112.04, 2202.06 (D).  A wash is encoded
                            as a hydrographic feature because it is an
                            integral part of a stream network, generally
                            found in arid areas and often associated with
                            intermittent drainage.  This code applies to
                            symbols 409(A), 141.6(B), 541.13(C), or
                            2202.06(D) only when the feature is labeled as a
                            wash.  Any single-line drainage that is found in
                            an areal wash, shown by symbol 541.14(C), is
                            coded as appropriate.  A wash is an ephemeral
                            drainage feature because it is normally dry, but
                            can contain runoff from heavy storms or snowmelt
                            for a few hours.  The edge of an areal wash
                            pattern is coded as apparent limit (050 0204),
                            unless the limits are defined by a hydrographic
                            feature such as a double-line intermittent
                            stream, then it is coded as right bank (050 0605)
                            or left bank (050 0606), and intermittent (050
                            0610).  Perennial features labeled as wash carry
                            only the perennial stream code.  Sand areas
                            adjacent to double-line perennial streams are not
                            coded as washes, but as sand in the Non-
                            Vegetative Features category.

               050 0421     Lake or pond
                            This code identifies a natural body of water of
                            any size.  Lakes or ponds are shown by symbols
                            410, 411, 412, 414 (A); 134.7, 141.12, 141.13,
                            141.14 (B); 541.23, 541.25, 541.26 (C); or
                            2203.03, 2203.04, 2203.05, 2203.06 (D).  This
                            classification includes also impounded rivers
                            that are labeled "Lake."  A lake or pond that is
                            0.030 inch or less in diameter is digitized as a
                            degenerate line.  If the lake or pond is 0.030
                            inch or less in diameter and has a drain
                            attached, it is digitized as a node.  Any lake or
                            pond larger than 0.030 inch is digitized as an
                            area feature.  The limits of the lake or pond are
                            coded with the appropriate shoreline code.

               050 0422     Coral reef
                            This code identifies a coral reef or rock reef
                            shown by symbols 233, 234 (A); 135.8, 112.100 (B);
                            512.135, 517.2, 517.3, 535.11 (C); or 2113.02(D).
                            A coral reef or rock reef is digitized as an area
                            if greater than 0.030 inch in diameter.  An
                            unattributed line is digitized around the outside
                            of the reef pattern.  If there is a brown tint
                            inside the reef pattern, the inference is that the
                            reef uncovers at low water and the area should also
                            be coded as "flat" (050 0115).  If there is no
                            brown tint inside of the reef pattern, the
                            inference is that the reef is always submerged and
                            the area should be coded only (050 0422).  If the
                            coral reef or rock reef is shown by a symbol of
                            0.030 inches or less, it is digitized as a
                            degenerate line.

               050 0423     Sand in open water
                            The code identifies an area of sand in other than
                            tidal waters.  It is shown by symbols 322(A),
                            134.3(B), 534.4(C), or 2112.03(D).  The sand is
                            digitized as an area if greater than 0.030 inch in
                            diameter or as a degenerate line if 0.030 inch or
                            less.  The edge of the sand pattern is digitized as
                            an apparent limit (050 0204) unless defined by a
                            hydrographic limiting feature.

               050 0424     Spoil area, dredged area, or dump area
                            This code identifies a feature labeled "Spoil
                            area", "Dredged area" or "Dump area."  When shown
                            by symbols 401(A) or 2203.02(D), it is digitized as
                            a line.  If shown by symbols 112.95(B) or
                            512.157(C), with or without blue tint in the
                            enclosed area, it digitized as an area.  When shown
                            by two parallel dashed black lines without blue
                            tint between
                            them, it is also digitized as an area with a
                            closure line on each end.  Lines depicting the
                            limits of the area are unattributed.  By
                            definition, spoil areas are located in water
                            areas and therefore are not double coded.

               050 0425     Fish ladder
                            This code describes a feature shown by symbol
                            512.39(C) or shown as a labeled portion of a
                            stream.  When symbol 512.39(C) is depicted, the
                            outline is coded 050 0201 (manmade shoreline) if
                            shown in black or 050 0200 (shoreline) if shown
                            in blue, and the area inside is coded with this
                            attribute.  When a section of a double-line
                            stream is labeled, the upstream and downstream
                            area limits are digitized as a closure line (050
                            0202), the shoreline is coded right bank or left
                            bank (050 0605, 050 0606), and the area is
                            attributed with this code.  If a portion of a
                            single-line stream is labeled, unattributed nodes
                            are placed at the upstream and downstream limits,
                            and the linear portion of this feature is
                            attributed with this code.  A fish ladder, that
                            is symbolized as a labeled portion of a stream
                            feature, is not double coded with the stream
                            code.

               050 0426     Holiday area
                            This code identifies an inadequate survey area
                            feature shown by symbols 112.93(B) or 512.153(C)
                            and labeled "holiday area."  The limits of this
                            area are uncoded.

  3.5.7        Descriptive Attribute Codes - apply to multiple types of
                 feature
               050 0601     Underground
                            This code describes a feature that is labeled
                            "underground" other than a tunnel, such as an
                            underground aqueduct shown by symbols 423(A),
                            141.21(B), 541.34(C), or 2204.07(D).  This code
                            is not used to describe a portion of a feature
                            that is placed underground to pass under another
                            feature.  (See code 050 0617.)

               050 0602     Overpassing
                            This code describes a feature or section of a
                            feature that passes over rather than intersects
                            another feature.  The code is generally applied
                            to a linear hydrographic feature carried over
                            another feature in a manmade object, such as an
                            aqueduct over a stream.  The code is applied only
                            to the overpassing portion of a longer elevated
                            feature or to a section of a feature between wing
                            ticks that is raised just to cross the
                            obstruction.  In some instances, such as a
                            double-line stream passing over an aqueduct, the
                            relationship of the feature is shown more simply
                            by using code 050 0617 on the underpassing
                            feature rather than using the overpassing code,
                            because only one of the two conditions need be
                            coded.

               050 0603     Elevated
                            This code describes a feature that is raised
                            above ground level and is either labeled
                            "elevated," or has wing ticks to indicate the
                            elevated portion, as in symbols 425(A),
                            141.22(B), or 2204.09(D).  This code is not used
                            to describe any portion of a feature that is
                            raised at some point in order to pass over
                            another feature.  (See code 050 0602.)

               050 0604     Tunnel
                            This code describes any portion of a feature that
                            is carried through a tunnel as indicated by
                            symbols 424(A), 141.23(B), 541.35(C), or
                            2204.08(D) or by a label.  The code applies only
                            to the portion of the feature that is in the
                            tunnel.  The concept of a tunnel conveys the idea
                            of underground or underpassing.  Therefore the
                            additional attributes 050 0601 or 050 0617 are
                            not used.

               050 0605     Right bank
                            This code describes the limit of a double-line
                            feature, such as a stream, that would be on the
                            right side if one were facing downstream.

               050 0606     Left bank
                            This code describes the limit of a double-line
                            feature, such as a stream, that would be on the
                            left side if one were facing downstream.

               050 0607     Under construction
                            This code describes any feature that has a label
                            indicating that it was under construction at the
                            time the map was made, typically canals or dams.

               050 0608     Salt
                            This code describes any feature, such as a marsh
                            or well, that is labeled "salt."

               050 0609     Unsurveyed
                            This code describes stream features shown by
                            symbols 408(A); 141.5(B); 541.03, 541.10, 541.11
                            (C); or 2202.05(D); which indicates a stream is
                            unsurveyed, or any other feature that is labeled
                            "unsurveyed."

               050 0610     Intermittent
                            This code describes any hydrographic feature,
                            such as stream, pond, or canal, that is depicted
                            by an intermittent symbol, such as 405, 412, 417,
                            420 (A); 141.6(B); 541.7, 541.32 (C); or 2202.02,
                            2203.05, 2204.02, 2204.05 (D).  This code
                            overrides the default value of "perennial" that
                            is assumed in the basic codes.

               050 0611     Abandoned or discontinued
                            This code describes any feature that is labeled
                            "abandoned" or "discontinued."

               050 0612     Submerged or sunken
                            This code describes any hydrographic feature that
                            was overprinted by blue tint to indicate it is
                            submerged, such as a marsh or an old river course
                            in an impounded water area.  This code is not
                            used to define water channels (050 0419).  It is
                            also used to describe features labeled "sunken." 
                            The outline of the submerged river course is
                            generally digitized as an unattributed line.

               050 0614     Dry
                            This code describes any feature that is labeled
                            "Dry," such as a dry lake, shown by symbols
                            134.7(B) or 534.5(C), or dry well.

               050 0615     Mineral or hot (sulphur, alkali, and so on)
                            This code describes any well, spring, or water
                            source that is labeled to indicate the water is
                            hot or contains minerals.  The labels vary
                            according to the substance in the water.

               050 0616     Navigable - transportation
                            This code describes any canal that is labeled as
                            navigable and is therefore a transportation
                            feature.  It is also used for channels intended
                            for transportation, such as the Intracoastal
                            Waterway.

               050 0617     Underpassing
                            This code describes a feature or a section of a
                            feature that passes underneath, rather than
                            intersects, another feature.  This code is
                            generally applied to a linear feature, such as an
                            aqueduct under a canal.  In some cases, such as
                            a single-line stream passing under a siphon, the
                            relationship is more simply shown by using code
                            050 0602 on the overpassing feature rather than
                            using the underpassing code, because only one of
                            the two conditions need be coded.

               050 0618     Earthen construction
                            This code describes a dam that is earthen in
                            construction as is shown in symbols 313(A),
                            132.14(B), 532.9(C), or 2302.08(D).  This feature
                            must consist of two or more contours that are
                            shown parallel to a straightened or near-
                            straightened portion of the shoreline (which may
                            or may not have a perennial drain attached) and
                            (or) be labeled as a dam.  This code (050 0618)
                            and the code for dam (050 0406) are assigned to
                            the straightened portion of the shoreline that
                            parallels the contours.  This code (050 0618) and
                            the code for dam (050 0406) are also assigned to
                            the portion of the shoreline of a lake or pond
                            that is shown by a brown line.  Do not apply this
                            code to the shoreline of a lake or pond that is
                            too small to require an interpolated elevation
                            (050 0619) and that has an intermittent stream
                            attached, for example, a stock pond.

               050 0619     Interpolated elevation
                            This code identifies a water surface elevation
                            that is not printed on the graphic source but has
                            been interpolated from adjacent hypsography.




                            Interpolated elevations are applied when required
                            to perennial and intermittent lakes, ponds,
                            reservoirs, and other impounded bodies of water
                            meeting a minimum size of 0.500 inch at map
                            scale.

               The following descriptive attribute codes represent
               decimal fractions of feet or meters.  They must only be
               used in conjunction with the elevation or river mile mark
               parameter attribute codes and only when the original
               elevations or river mile marks are expressed to decimal
               fractions or when applying interpolated elevations in
               extremely flat areas.  The units will be the same as those
               of the corresponding parameter code.

                                050 0621   .1
                                050 0622   .2
                                050 0623   .3
                                050 0624   .4
                                050 0625   .5
                                050 0626   .6
                                050 0627   .7
                                050 0628   .8
                                050 0629   .9


  3.5.8        Parameter Attribute Codes
               05N ----     Elevation of actual, interpolated, or predicted
                            water  surface
                            This code is used for the value of the water
                            surface elevation shown on bodies of water.  The
                            value may be shown as "normal pool elevation
                            XXX," "elevation XXXX," or simply as a value
                            printed in blue or black.  This code is also used
                            for the value of the maximum potential water
                            surface elevation shown on the indefinite
                            shoreline defining the limits of an area subject
                            to controlled inundation. The digitizer enters a
                            value in place of the "N" in the major code as
                            follows:
                               1 = whole feet
                               2 = whole meters
                               6 = whole feet below datum
                               7 = whole meters below datum
                            The elevation value is then entered into the
                            minor code, flush right.  If a value in feet
                            exceeds four digits, it is converted to meters. 
                            To express elevations in decimal feet or meters,
                            use this parameter code in conjunction with
                            descriptive attribute codes 050 0621 through 050
                            0629.

               055 ----     River mile mark
                            This code identifies a river mile mark as shown by
                            symbol 512.109(C).  The point is placed on the
                            black cross next to the label "Mile NNN."  If the
                            cross occurs in the area of a double-line stream
                            it is digitized as a degenerate line.  If the
                            cross occurs directly on a line that is also being
                            digitized, the point is digitized as a node on
                            that line.  When the river mile mark is expressed
                            to a decimal fraction, use this code 055 xxxx for
                            the nondecimal value and 050 0621 through 050 0629
                            for the decimal value.  Enter the value in the
                            minor code flush right.  If the source material
                            has the value shown at intervals, such as at every
                            fifth mark, the digitizer assigns the appropriate
                            value to each mark.

               050 0000     Photorevised feature
                            This code is described in section 3.3.3.

               058 0000     Best estimate of classification or position
                            This code is described in section 3.3.3.

               059 00--     Coincident feature
                            This code is described in section 3.3.3.

               This sheet represents pages 3-14, which is blank

  (Current version containing all changes through 11/15/93)

  3.6            VEGETATIVE SURFACE COVER--MAJOR CODE 070

                 Features that are collected under this code include woods
                 or brush-wood, scrub, orchards or plantations, scattered
                 trees, and vineyards.  Additional vegetative features that
                 are associated with wetland or submerged areas, such as
                 marshes and swamps, rice fields, mangrove, and cranberry
                 bogs, are collected under hydrography, major code 050.

  3.6.1          General Principles
                 Vegetative surface cover information is shown on the map
                 source as an area of pattern or tint.  Each area is
                 digitized by following the edge of the open-window
                 separate.  If the open-window separate is not available,
                 the line is digitized following the outline of the pattern
                  or tint as closely as possible.  The digitized line
                 depicting the limits of the vegetative feature is
  3.6            VEGETATIVE SURFACE COVER--MAJOR CODE 070

                 Features that are collected under this code include woods
                 or brush-wood, scrub, orchards or plantations, scattered
                 trees, and vineyards.  Additional vegetative features that
                 are associated with wetland or submerged areas, such as
                 marshes and swamps, rice fields, mangrove, and cranberry
                 bogs, are collected under hydrography, major code 050.

  3.6.1          General Principles
                 Vegetative surface cover information is shown on the map
                 source as an area of pattern or tint.  Each area is
                 digitized by following the edge of the open-window
                 separate.  If the open-window separate is not available,
                 the line is digitized following the outline of the pattern
                  or tint as closely as possible.  The digitized line
                 are associated with wetland or submerged areas, such as
                 marshes and swamps, rice fields, mangrove, and cranberry
                 bogs, are collected under hydrography, major code 050.

  3.6.1          General Principles
                 Vegetative surface cover information is shown on the map
                 source as an area of pattern or tint.  Each area is
                 digitized by following the edge of the open-window
                 separate.  If the open-window separate is not available,
                 the line is digitized following the outline of the pattern
                  or tint as closely as possible.  The digitized line
                 depicting the limits of the vegetative feature is
                 depicting the limits of the vegetative feature is
                 unattributed.  However, the line digitized between
                 features, to retain the separate identity of each, is
                 coded as a closure line (070 0200).  See figure 3-2.  Note
                 that in the vegetative surface cover category, there are
                 no photorevised features shown in purple.  Photorevised
                 vegetation is shown in green and not distinguishable as
                 such.

  3.6.1.1        Vegetative Surface Cover Attribute Codes
  3.6.1.1        Vegetative Surface Cover Attribute Codes
                 The attribute codes authorized for use in digitizing the
                 vegetative surface cover category are listed in this
                 section.  The instructions for the use of the attribute
                 codes are given in section 3.6.2 through 3.6.8.

                    o  Node attribute codes
                             None

                    o  Area attribute codes
                             000 0000  Outside area
                             070 0101  Woods or brushwood
                             070 0102  Scrub
                             070 0103  Orchard or plantation
                             070 0104  Vineyard
                             070 0105  Scattered trees
                             070 0106  Void area

                    o  Line attribute codes
                             070 0200  Closure line
                             070 0299  Processing line


                    o  Single-point attribute codes
                             None

                    o  General purpose attribute codes
                             None

                    o  Descriptive attribute codes
                             None

                    o  Parameter attribute codes
                             078 0000  Best estimate of position or
                             classification
                             079 00--  Coincident feature


  3.6.2        Node Attribute Codes
               There are no attribute codes for nodes in this category.
  
  3.6.3        Area Attribute Codes
               000 0000     Outside area
                            This code is described in section 3.3.3.

               070 0101     Woods or brushwood
                            Wooded areas contain tree cover or brush that is
                            potential tree cover.  The growth is at least 6
                            feet tall, is dense enough to afford cover for
                            troops, and has a minimum density between 20 and
                            35 percent.  Woods are shown by symbols 600,
                            604(A); 152.1, 152.2, 152.3, 152.5(B); 552.1,
                            552.2, 552.3, 552.5(C); or 2402.01(D).

                            Woods which overprint swamp, submerged swamp, or
                            open water areas will be delineated as separate
                            from any contiguous wooded areas and will be
                            coded as coincident with the hydrographic overlay
                            as shown in Figure 3.2.

               070 0102     Scrub
                            Scrub areas are covered with low-growing or
                            stunted perennial vegetation such as cactus,
                            mesquite, or sagebrush.  Scrub is common in arid
                            areas and usually is not mixed with woods.  It is
                            shown by symbols 603(A); 154.1(B), 554.1(C), or
                            2402.05(D).

               070 0103     Orchard or plantation
                            Orchard or plantation areas consist of evenly
                            spaced trees or tall bushes that bear fruit or
                            nuts.  Plantings of trees that are called groves
                            are included in this type.  These features are
                            shown by symbols 601(A), 155.1(B), 555.1(C), or
                            2402.03(D).


















    
                                                Area      Parameter
     Area             Feature                 attribute   attribute
                                                code        code

      1           Woods                       070 0101     None
      2           Submerged woods,
                    submerged wooded swamp,
                    wooded swamp              070 0101     079 0005*
   3, 4, 5        Not digitized in this
                    category
    * This code does not apply to 1:100,000-scale maps.



                              Figure 3-2
    Attribute and parameter coding for woods, submerged woods, 
            wooded swamp and submerged wooded swamp


               070 0104     Vineyard
                            Vineyards are plantings of grapevines or other
                            kinds of cultivated climbing plants, such as
                            berry vines and hops, supported and arranged
                            evenly in rows.  Vineyards are shown by symbols
                            602(A), 156.1(B), 556.1(C), or 2402.04(D).

               070 0105     Scattered trees
                            Scattered trees are woods or brushwood that are
                            less than the minimum density required for woods
                            (code 070 0101).  Scattered trees are shown by
                            symbol 553.1(C).

               070 0106     Void area
                            This code identifies the area on the source
                            material where vegetative surface cover data do
                            not exist because of replacement by imagery. 
                            This code is also used to identify the area
                            beyond the national boundary to distinguish it
                            from the background area.  The closure line that
                            defines the void area beyond the national
                            boundary is coded as coincident with the
                            Boundaries category (079 0009).

  3.6.4        Line Attribute Codes
               070 0200     Closure line
                            This code describes a line digitized to define
                            the perimeter of void areas that are not
                            otherwise explicitly symbolized.  This code also
                            describes a line segment digitized between
                            vegetative features to retain separate identity
                            of each.  See figure 3-2.

               070 0299     Processing line
                            Some routines in the processing system (PROSYS)
                            have limitations on the number of lines, nodes,
                            or areas that can be processed.  For example, an
                            area may be associated with no more than 4,751
                            lines.  This code identifies a line or lines
                            digitized to segment the data within a file to
                            create more background areas, thereby enabling
                            large files to be processed.

  3.6.5        Single-Point Attribute Codes
               There are no single-point attribute codes for this
               category.
  
  3.6.6        General Purpose Attribute Codes
               There are no general purpose attribute codes for this
               category.

  3.6.7        Descriptive Attribute Codes
               There are no descriptive attribute codes for this
               category.

  3.6.8        Parameter Attribute Codes
               078 0000     Best estimate of position or classification
                            This code is described in section 3.3.3.

               079 00--     Coincident feature
                            This code is described in section 3.3.3.  For the
                            Vegetative Surface Cover category, the coincident
                            feature parameter code is used for wooded swamps,
                            submerged wooded swamps, or submerged woods. 
                            Figure 3-2 depicts an example.




  (Current version containing all changes through 11/15/93)



  3.7       NON-VEGETATIVE FEATURES--MAJOR CODE 080

  3.7.1     General Principles
            The purpose in digitizing non-vegetative features is to
            collect information about the natural surface of the Earth
            as symbolized on the map.  This includes lava, sand, and
            gravel features.  Numerous other non-vegetative features
            are included in the categories of Hydrography (major code
            050) and Manmade Features (major code 200).  Vegetative
            surface features are in the category of Vegetative Surface
            Cover (major code 070).

            The non-vegetative features information is primarily
            digitized as distinct areas (polygons) identified by an
            attribute code assigned to a point within the area.  The
            outline of the area is digitized from the open-window
            separate used to prepare the map.  If the separate is not
            available, the line is digitized by following the outline
            of the symbolized area as closely as possible.  The
            outline of the coded area is not given an attribute code,
            unless it is coincident with a linear feature in another
            category.  Non-vegetative features symbolized as point
            features, such as natural arches, are also digitized in
            this category.

  3.7.1.1   Non-Vegetative Features Attribute Codes
            The attribute codes authorized for use in digitizing non-
            vegetative features are listed in this section and the
            instructions for the use of the codes are given in
            sections 3.7.2 through 3.7.8.

               o  Node attribute codes
                    None

               o  Area attribute codes
                    000 0000  Outside area
                    080 0100  Glacial moraine
                    080 0101  Gravel beach
                    080 0102  Sand area or beach
                    080 0103  Shifting sand or dune area
                    080 0104  Lava
                    080 0105  Void area
  
               o  Line attribute codes
                    080 0200  Closure line
                    080 0299  Processing line
  
               o  Single-point attribute codes (degenerate line)
                    080 0300  Located surface feature
  
               o  General purpose attribute codes
                    None
  
               o  Descriptive attribute codes
                    None
  
               o  Parameter attribute codes
                    080 0000  Photorevised feature
                    088 0000  Best estimate of position or
                    classification
                    089 00--  Coincident feature

  3.7.2   Node Attribute Codes
          There are no attribute codes for nodes in this category.

  3.7.3   Area Attribute Codes
          000 0000   Outside area
                     This code is described in section 3.3.3.

          080 0100   Glacial moraine
                     A glacial moraine is an area of gravel deposited
                     by a glacier.  The glacier symbol (see code 050
                     0103) may be adjacent to the moraine.  Areas
                     where the glacial moraine
                     pattern overlaps a glacier are coded coincident
                     with the hydrography category  (080 0005).  The
                     moraine is shown by symbols 320(A), 134.4(B), or
                     537.2(C).  However, on 1:100,000-scale maps, the
                     symbol is not labeled.  Therefore, the feature
                     must be examined with respect to the surrounding
                     area to identify a moraine correctly.

          080 0101   Gravel beach
                     This code identifies an area shown by the gravel
                     pattern USGS 22 or by symbols 329(A), 134(B),
                     537.1(C), or 2112.03(D) and labeled "gravel." 
                     Note that on 1:100,000-scale maps, the sand and
                     gravel beaches are shown by the sand pattern USGS
                     17 and the only distinction made between them is
                     the label "gravel."

          080 0102   Sand area or beach
                     This code identifies an area shown by the sand
                     pattern, USGS 17 or by symbols 316(A), 134.3(B),
                     or 534.1(C).  A sand beach is not labeled on
                     1:24,000-scale maps, nor is there a separate
                     symbol number, but is usually found bordering a
                     large water body.  On 1:100,000-scale maps, this
                     code is used for all beaches as shown in symbol
                     134.5(B).  On P-Maps this code is used for all
                     areas and beaches as shown by symbol 2112.03(D)
                     and labeled "sand."

          080 0103   Shifting sand or dune area
                     This code identifies an area shown by symbols
                     331(A), 134.6(B), 534.2(C), or 2112.03(D).  Each
                     symbol carries the label "sand dunes."  On older
                     maps shifting sand may be shown by USGS 17A,
                     which is no longer in use.  Such areas are also
                     identified by this code.

          080 0104   Lava
                     This code identifies an area shown by symbols
                     328(A), 135.5(B), 535.6(C), or 2112.07(D) or
                     outlined by symbol 532.24(C), all labeled "Lava." 
                     Such areas must be labeled to have this code
                     assigned because the disturbed surface symbols
                     are used for other features.

          080 0105   Void area
                     This code identifies an area on the source
                     material, beyond the national boundary, where
                     non-vegetative feature data do not exist because
                     of replacement by imagery.  This code is also
                     used to identify the area beyond the national
                     boundary to distinguish it from the background
                     area.  The closure line that defines the void
                     area beyond the national boundary is coded as
                     coincident with the Boundaries category (089
                     0009).

  3.7.4   Line Attribute Codes
          080 0200   Closure line
                     This code describes a line digitized to define
                     the perimeter of void areas that is not otherwise
                     explicitly symbolized.

          080 0299   Processing line
                     Some routines in the processing system software
                     (PROSYS) have limitations on the number of lines,
                     nodes, or areas that can be processed.  For
                     example, an area may be associated with no more
                     than 4,751 lines.  This code describes a line or
                     lines digitized to segment the data within a file
                     to create more background areas, thereby enabling
                     large files to be processed.

  3.7.5   Single-Point Attribute Codes
          080 0300   Located surface feature
                     This code describes a point placed on a landmark
                     surface feature that is shown by symbols 198(A),
                     112.4(B), 412.72(C), or 2111.03(D) and labeled. 
                     Landmark surface features may include natural
                     arches and natural bridges, which are not
                     otherwise symbolized.

  3.7.6   General Purpose Attribute Codes
          There are no general purpose attribute codes in this
          category.

  3.7.7   Descriptive Attribute Codes
          There are no descriptive attribute codes in this category.

  3.7.8   Parameter Attribute Codes
          080 0000   Photorevised feature
                     This code is defined in section 3.3.3.

          088 0000   Best estimate of position or classification
                     This code is defined in section 3.3.3.

          089 00--   Coincident feature
                     This code is defined in section 3.3.3.




  (Current version containing all changes through 11/15/93)



  3.8       BOUNDARIES--MAJOR CODE 090

  3.8.1     General Principles
            The purpose of digitizing boundaries is to convert into
            digital form the point and line information, displayed on
            a map source, that is part of the National Mapping
            Division base category denominated as boundaries.  Map
            information normally considered to be in other base
            categories, but using symbology similar to that found in
            the boundaries category, e.g., cemetery, ruins, and
            drive-in theatre limits, is not included in the boundaries
            category.
  
            Counties, or county equivalents, may be divided into minor
            civil subdivisions.  Quadrangle maps show only
            subdivisions that are reasonably stable.  Incorporated
            places includes cities, towns, and villages, which may be
            subdivisions of the county, town, or township wherein they
            are located or may be coextensive with them or
            independent.
  
            Hawaii is divided into five counties.  Four of the
            counties are subdivided into districts.  Districts are
            subdivided into smaller areas called ahupuaas, and
            ahupuaas are subdivided into small land divisions called
            ilis and leles.  The boundaries of ilis and leles are not
            collected.  A further land subdivision shown on 1:24,000-
            Scale maps in Hawaii is the homestead.  The homesteads are
            much smaller than the ahupuaas, generally less than a
            square mile.

            Line attribute codes are not attached to a boundary if
            they are implicitly defined by its bounding areas.  For
            example, a civil township boundary is deducible as such
            from the area codes on either side of it.  However,
            boundary lines that are coincident with features from
            other categories or that have been revised have the
            appropriate parameter or descriptive codes attached to the
            line segment itself, i.e., 099 00   or 090 0000.

            Boundaries are described in Topographic Instructions,
            Chapter 4a3, Boundaries on 1:24,000-Scale Maps (January
            1980).

  3.8.1.1   Boundaries Attribute Codes
            The attribute codes used in digitizing boundary
            information are listed in this section.  Instructions for
            the use of the attribute codes are given in sections 3.8.2
            through 3.8.6.

             o  Node attribute codes
                  090 0001  Monumented point on a boundary

             o  Area attribute codes
                  000 0000  Outside area
                  090 0100  Civil township, district, precinct, or
                            barrio
                  090 0101  Incorporated city, village, town,
                            borough, or hamlet
                  090 0103  National park, monument, lakeshore,
                            seashore,
                            parkway, battlefield, or recreation area
                  090 0104  National forest or grassland
                  090 0105  National wildlife refuge, wildlife
                            management area,
                            game preserve, or fish hatchery
                  090 0106  National scenic waterway, riverway, wild
                            and scenic river, or wilderness area
                  090 0107  Indian reservation
                  090 0108  Military reservation
                  090 0110  Federal prison
                  090 0111  Miscellaneous Federal reservation
                  090 0129  Miscellaneous State reservation
                  090 0130  State park, recreation area, arboretum,
                            or lake
                  090 0131  State wildlife refuge, wildlife
                            management area,
                            game preserve, or fish hatchery
                  090 0132  State forest or grassland
                  090 0133  State prison
                  090 0134  County game preserve
                  090 0135  Ahupuaa (Hawaii)
                  090 0136  Hawaiian homestead
                  090 0150  Large park (city, county, or private)
                  090 0151  Small park (city, county, or private)
                  090 0197  Canada
                  090 0198  Mexico
                  090 0199  Open water

             o  Line attribute codes
                  090 0201  Indefinite (or approximate) boundary
                  090 0202  Disputed boundary
                  090 0203  Historical line
                  090 0204  Boundary closure line
                  090 0299  Processing line

             o  Single-point attribute codes (degenerate line)
                  090 0301  Reference monuments for boundary points

             o  Parameter attribute codes
                  090 0000  Photorevised feature
                  091 00--  State or State equivalent FIPS code
                  092 0---  County or county equivalent FIPS code
                  093 00--  Civil township or civil township
                            equivalent FIPS code, first two digits
                  094 0---  Civil township or civil township
                            equivalent FIPS code, last three digits
                  095 ----  Monument number
                  096 XXYY  Alphabetic portion of any monument number
                            Substitute numeric equivalent of
                            alphabetic portion for XX and for YY as follows:  
                            00 = blank, 01 = A, 02 = B, 03 = C, 04 = D, 
                            05 = E, 06 = F, 07 = G, 08 = H, 09 = I, 10 = J, 
                            11 = K, 12 = L, 13 = M, 14 = N, 15 = O, 16 = P, 
                            17 = Q, 18 = R, 19 = S, 20 = T, 21 = U, 22 = V, 
                            23 = W, 24 = X, 25 = Y, 26 = Z.

                  098 0000  Best estimate of classification or position
                  099 00--  Coincident feature

  3.8.2   Node Attribute Codes
          090 0001   Monumented point on a boundary
                     This code describes a physical monument lying on
                     a boundary line.  This includes any of the
                     following:

               o  recovered section corners, quarter corners, closing
                  corners, angle points, or meander turning points
                  that fall on a boundary.  These monuments are
                  designated by symbols 506, 507, 510, 511, 523 (A);
                  523.5 through 523.7 (C); or 2502.07, 2502.08 (D). 
                  The coincidence code 099 0030 is also used.

               o  survey control stations on a boundary.  These
                  monuments are designated by symbols 216 through
                  219, 222, 223, 225 through 227, 230, 231 (A);
                  512.99 through 512.107 (C); or 2102.02 through
                  2102.04, 2102.06 through 2102.09, 2102.12 (D).  The
                  coincidence code 099 0015 is used in all cases, and
                  coincidence code 099 0030 is also used if the
                  monument is coincident with the U.S. Public Land
                  Survey System.

               o  land grant monuments on a boundary.  These
                  monuments are designated by symbols 501(A) or
                  2502.02(D).  The coincidence code 099 0030 is used. 
                  Land grants are digitized as part of Public Lands.

               o  any other point represented with a red or black
                  boundary monument symbol.  If the monument is
                  numbered, also use code 095 ----.

  3.8.3   Area Attribute Codes
          000 0000   Outside area
                     This code is described in section 3.3.3.

          090 0100   Civil township, district, precinct, or barrio
                     This code identifies a point placed within an
                     area delineated by symbols 205(A), 112.77(B),
                     512.126(C), or 2107.03(D).

          090 0101   Incorporated city, village, town, borough, or
                     hamlet
                     This code identifies a point placed within an
                     area delineated by symbols 206(A), 112.77(B),
                     512.127(C), or 2107.04(D).

          090 0103   National park, monument, lakeshore, seashore,
                     parkway, battlefield, or recreation area
                     This code identifies a point placed within a
                     national park, national monument, national
                     recreation area, national seashore or lakeshore,
                     national historic site, national parkway, or
                     national battlefield.  The following national
                     areas are normally administered by the National
                     Park Service and can be included under the
                     national park attribute code:  historic parks and
                     places, memorial parks, natural landmarks, and
                     national preserves.  National cemeteries are
                     included under the national park code and are
                     given the coincidence code 099 0020.  All areas
                     with pink stippling along the boundary should be
                     included under national parks unless the area
                     label falls within one of the other Federal area
                     categories.  National park areas are delineated
                     by symbols 207(A), 112.78(B), 512.128(C), or
                     2107.05(D).

          090 0104   National forest or grassland
                     This code identifies a point placed within a
                     national forest or grassland delineated by
                     symbols 207(A), 112.78(B), 512.128(C), or
                     2107.05(D).

          090 0105   National wildlife refuge, wildlife management
                     area, game preserve, or fish hatchery
                     This code identifies a point placed within a
                     wildlife recreation or management area, fish
                     hatchery, animal range, or refuge for specific
                     animals, and is delineated by symbols 207(A),
                     112.78(B), 512.128(C), or 2107.05(D).

          090 0106   National scenic waterway, riverway, wild and
                     scenic river, or wilderness area
                     This code identifies a point placed within a
                     national scenic waterway, riverway, wild and
                     scenic river, or wilderness area.  These areas
                     are delineated by symbols 207(A), 112.78(B),
                     512.128(C), or 2107.05(D).

          090 0107   Indian reservation
                     This code identifies a point placed within an
                     Indian reservation, including those that have
                     boundaries symbolized with a solid red line.  If
                     the solid red line is labeled with the name "Old
                     Indian Reservation Boundary" it should be
                     assigned only the historical line code (see code
                     090 0203). Rancherias and Indian allotments are
                     types of Indian reservations, all of which are
                     delineated by symbols 207(A), 112.78(B),
                     512.128(C), or 2107.05(D).

          090 0108   Military reservation
                     This code identifies a point placed within a
                     military reservation.  Examples are:  forts,
                     bases, weapons stations, Coast Guard stations,
                     and bombing and gunnery ranges.  These areas are
                     delineated by symbols 207(A), 112.78(B),
                     512.128(C), or 2107.05(D).

          090 0110   Federal prison
                     This code identifies a point placed within a
                     Federal prison delineated by symbols 207(A),
                     112.78(B), 512.128(C), or 2107.05(D).

          090 0111   Miscellaneous Federal reservation
                     This code identifies a point placed within a
                     Federal government reservation not included in
                     any other Federal area category.  An example is
                     a veterans hospital.  This code and code 090 0129
                     replace previous code 090 0109, Non-military
                     Government Reservation.  The area is delineated
                     by symbols 207(A), 112.78(B), 512.128(C), or
                     2107.05(D).

          090 0129   Miscellaneous State reservation
                     This code identifies a point placed within a
                     State equivalent government reservation not
                     included in any other State area category.  An
                     example is State hospital.  This code and code
                     090 0111 replace previous code 090 0109, Non-
                     military Government Reservation.  The area is
                     delineated by symbols 207(A), 112.78(B),
                     512.128(C), or 2107.05(D).

          090 0130   State park, recreation area, arboretum, or lake
                     This code identifies a point placed within a
                     State park, recreation area, arboretum, or lake
                     delineated by symbols 207(A), 112.78(B),
                     512.128(C), or 2107.05(D).

          090 0131   State wildlife refuge, wildlife management area,
                     game preserve, or fish hatchery
                     This code identifies a point placed within a
                     State wildlife refuge, wildlife management area,
                     fish hatchery, or game preserve delineated by
                     symbols 207(A), 112.78(B), 512.128(C), or
                     2107.05(D).

          090 0132   State forest or grassland
                     This code identifies a point placed within a
                     State forest or grassland delineated by symbols
                     207(A), 112.78(B), 512.128(C), or 2107.05(D).

          090 0133   State prison
                     This code identifies a point placed within a
                     State prison area delineated by symbols 207(A),
                     112.78(B), 512.128(C), or 2107.05(D).

          090 0134   County game preserve
                     This code identifies a point placed within a
                     county game preserve delineated by symbols 207,
                     209 (A); 512.128, 512.129 (C); or 2107.05,
                     2107.06 (D).

          090 0135   Ahupuaa (Hawaii)
                     This code identifies a point placed within an
                     area delineated by symbols 500(A), 112.78(B),
                     523.10(C), or 2502.01(D).  Code 300 0103 is not
                     used for ahupuaas because they are not part of
                     the Public Land Survey System.  More explanation
                     of this code is given in section 3.8.1.

          090 0136   Hawaiian homestead
                     This code identifies a point placed within an
                     area delineated by symbols 500(A), 112.78(A),
                     523.10(C), or 2502.01(D).  Codes 090 0111 and 090
                     0129 are not used for Hawaiian homesteads because
                     they are not reservations.  More explanation of
                     this code is given in section 3.8.1.

          090 0150   Large park (city, county, or private)
                     This code identifies a point placed within a
                     regional, city, county, or private park
                     delineated by symbols 207(A), 112.79(B),
                     512.128(C), or 2107.05(D).

          090 0151   Small park (city, county, or private)
                     This code identifies a point placed within a
                     regional, city, county, or private park
                     delineated by symbols 209(A), 512.129(C), or
                     2107.06(D).

          090 0197   Canada
                     This code identifies a point placed within the
                     boundaries of Canada.  The boundary between
                     Canada and the United States is identified by
                     symbols 202(A), 112.74(B), 512.123(C), or
                     2107.01(D).

          090 0198   Mexico
                     This code identifies a point placed within the
                     boundaries of Mexico.  The boundary between
                     Mexico and the United States is identified by
                     symbols 202(A), 112.74(B), 512.123(C), or
                     2107.01(D).

          090 0199   Open water
                     This code identifies a point placed within water
                     areas on coastal quadrangles, which are not
                     otherwise included within a coded area, such as
                     091 00xx-- State FIPS.

  3.8.4   Line Attribute Codes
          090 0201   Indefinite (or approximate) boundary
                     This code identifies a boundary for which the
                     accuracy of location does not meet National Map
                     Accuracy Standards for well-defined features. 
                     Indefinite boundaries of county rank or higher
                     appear on 1:100,000- and 1:24,000-scale maps with
                     standard symbolization but reduced to one-half
                     the specified lineweight and labeled "Indefinite
                     Boundary."  Those of less than county rank are
                     shown with normal symbolization and lineweight
                     and are labeled "Indefinite  Boundary." 
                     Boundaries labeled "Approximate" on
                     1:24,000-scale maps are included under this code. 
                     Indefinite boundaries are depicted by symbols
                     212(A), 112.80(B), or 512.130(C).

          090 0202   Disputed boundary
                     This code identifies a State, county, or national
                     reservation boundary that is unmarked and cannot
                     be located on the ground from other substantial
                     evidence, that has a disputed location, or that
                     the recorded description of cannot be reconciled
                     with local conditions.  Disputed boundaries are
                     labeled "Indefinite" on the map with an
                     additional marginal note.

          090 0203   Historical line
                     This code identifies boundary lines that have
                     some historical significance as indicated by a
                     label.  These include boundaries labeled with a
                     name, old Indian treaty or allotment lines,
                     historical State lines, and old military
                     reservation boundaries (shown in red).

          090 0204   Boundary closure line
                     This code identifies lines digitized to complete
                     unclosed boundaries.  In the case of national,
                     State, or county boundaries that stop at a
                     shoreline, the shoreline is
                     digitized and given this attribute.  The offshore
                     area is then given the appropriate area code.  In
                     the case where a national, State, or county
                     boundary is extended out from shore and dropped,
                     an arbitrary line is digitized by extending the
                     line from the drop point to the quadrangle
                     neatline and giving the new line the 090 0204
                     attribute code.  The water area within the
                     boundary is given the same code as the equivalent
                     land area.

          090 0299   Processing line
                     Some routines in the processing system (PROSYS)
                     have limitations on the number of lines, nodes,
                     or areas that can be processed.  For example, an
                     area may be associated with no more than 4,751
                     lines.  This code describes a line or lines
                     digitized to segment the data within a file to
                     create more background areas, thereby enabling
                     large files  to be processed.

  3.8.5   Single-Point Attribute Codes (degenerate lines)
          090 0301   Reference monuments for boundary points
                     This code identifies monumented points not on a
                     boundary line, but serving as references to
                     establish the location of points on the boundary. 
                     Reference monuments are delineated by symbols
                     226(A) or 512.105(C).  If the monument is
                     numbered, also use code 095 ----.

  3.8.6   Parameter Attribute Codes
          090 0000   Photorevised feature
                     This code is described in section 3.3.3.

          091 00--   State or State equivalent FIPS code
                     Enter the two-digit State or State equivalent
                     FIPS code.

          092 0---   County or county equivalent FIPS code
                     Enter the three-digit county or county equivalent
                     (e.g., parish, independent city) FIPS code.

          093 00--   Civil township or township equivalent FIPS code
                     Enter the first two of the five-digit township or
                     township equivalent FIPS code.

          094 0---   Civil township or township equivalent FIPS code
                     Enter the last three of the five-digit township
                     or township equivalent FIPS code.

          095 ----   Monument number
                     Enter the one- to four-digit monument number,
                     flush right.

          096 XXYY   Alphabetic portion of any monument number
                     This code is used to encode the alphabetic
                     portion of any monument number.  The code is used
                     in conjunction with the appropriate code 095 ----
                     if the monument designation is
                     mixed numeric and alphabetic.  The code can hold
                     one or two letters by substituting the numeric
                     equivalent 01 to 26 for the letters A to Z with
                     00 substituting for a blank.  If one letter is
                     encoded it will be entered in the YY portion of
                     the code with blank coded into the XX portion. 
                     The code precedes or follows the numeric portion
                     of the monument number in accordance with its
                     actual position.  In the case of an entirely
                     alphabetic monument designator, also use the FIPS
                     code to specify jurisdiction with 0000 entered
                     into the minor code.  The procedure for encoding
                     the alphabetic portion of a monument number is
                     identical to the procedure for encoding the
                     alphabetic portion of a route number as described
                     under code 177 XXYY.

          098 0000   Best estimate of classification or position
                     This code is described in section 3.3.3.

          099 00--   Coincident feature
                     This code is described in section 3.3.3.




  (Current version containing all changes through 11/15/93)



  3.9     SURVEY CONTROL AND MARKERS--MAJOR CODE 150

  3.9.1   General Principles
          The purpose of collecting Survey Control and Markers
          category data is to capture horizontal and vertical
          control information about the points of established
          horizontal and vertical positions that are used as fixed
          references in positioning and correlating map features. 
          The vertical control data are digitized from the graphic
          source, and the survey control markers with horizontal
          control data are derived from ancillary source (i.e.,
          geodetic control sheets).  Not included are elevation data
          of less than third order, such as spot elevations, or the
          "T" and "AT" spot elevations on provisional maps.

          The features in this category are generally digitized as
          single-point features, also called degenerate lines.  When
          these features are located directly on a linear feature in
          this overlay, they are collected as node elements.  Each
          single-point feature is assigned a code to describe the
          type of control point or marker and appropriate parameter
          codes to designate the location and elevation.  Each
          single- point feature is also assigned the State and
          county FIPS codes.

          Several of the control points and markers are coincident
          with points in the U.S. Public Land Survey System or in
          the Boundaries category.  Such features are also assigned
          the coincident feature code.  The list of codes used is in
          section 3.9.1.1 and instructions for their use are in
          sections 3.9.2 through 3.9.8.

          The codes that describe a photorevised feature and a best
          estimate of position/classification are not used in this
          category.

          Only one of the codes in this section is applicable to
          1:100,000-scale maps, code 150 0331.

  3.9.1.1 Survey Control and Markers Attribute Codes
          The attribute codes used in digitizing survey control
          features are listed in this section.  Instructions for the
          use of the attribute codes are given in sections 3.9.2
          through 3.9.8.

             o  Node attribute codes
                  None  (See 3.9.1)

             o  Area attribute codes
                  000 0000  Outside area
                  150 0100  Void area

             o  Line attribute codes
                  150 0200  Closure line

             o  Single-point attribute codes
                  150 0300  Horizontal control station, third order
                            or better, permanent mark
                  150 0301  Horizontal and vertical control station,
                            third order or better
                  150 0302  Horizontal control station, vertical
                            angle bench mark (VABM)
                  150 0303  Horizontal control station, checked spot
                            elevation
                  150 0310  Vertical control station, third order or
                            better, tablet
                  150 0311  Vertical control station, recoverable
                            mark, third order or better, no tablet
                  150 0320  Boundary monument, third order or better,
                            tablet
                  150 0321  Boundary monument, third order or better,
                            no tablet
                  150 0330  Reference monument
                  150 0331  U.S. mineral or location monument
                  150 0332  Other control point

             o  General purpose attribute codes
                  None

             o  Descriptive attribute codes
                  150 0601 - 150 0609  Fractions of elevation values

             o  Parameter attribute codes
                  151 ----  State or State equivalent FIPS code
                  152 ----  County or county equivalent FIPS code
                  153 ----  Elevation in feet
                  154 ----  Elevation in meters
                  155 ----  Elevation in feet below datum
                  156 ----  Elevation minus 10,000 for elevations
                            greater than 9,999 feet
                  157 ----  Elevation in meters below datum
                  159 00--  Coincident feature

  3.9.2   Node Attribute Codes
          There are generally no node attribute codes in this
          category.  However, single-point features, which are
          generally digitized as degenerate line elements, are
          digitized as node elements when located on a line (200 -
          closure line) in this category.  See sections 3.9.3,
          3.9.4, and 3.9.5 for additional information.

  3.9.3   Area Attribute Codes
          000 0000   Outside area
                     This code is described in section 3.3.3.

          150 0100   Void area
                     This code identifies an area on the source
                     material where no survey control data exist
                     because of replacement by imagery or a pattern
                     from another category.  A void area is also found
                     beyond the national boundary to distinguish it
                     from the background area.  Where appropriate, the
                     perimeter of the void area, a closure line, is
                     coded as coincident with the category that
                     defines the survey control void area.  The
                     closure line that defines the void area beyond
                     the national boundary is coded as coincident with
                     the Boundaries category (159 0009).

  3.9.4   Line Attribute Codes
          150 0200   Closure line
                     This code describes a line digitized to define
                     the perimeter of void areas.

  3.9.5   Single-Point Attribute Codes
          Although the following single-point features are generally
          digitized as degenerate line elements, they are digitized
          as node elements when located on a line (200 - closure)
          collected in this category.

          150 0300   Horizontal control station, third order or
                     better, permanent mark
                     This code identifies a degenerate line placed on
                     a horizontal control station of third order or
                     better with a permanent mark.  It is shown by
                     symbols 216(A), 512.99(C), or 2102.03(D).  If the
                     control station is coincident with a section
                     corner as shown by symbols 229(A) or 512.101(C)
                     also use code 159 0030.

          150 0301   Horizontal and vertical control station, third
                     order or better
                     This code identifies a degenerate line placed on
                     a horizontal control station having elevation
                     data of third order or better and labeled BM
                     (benchmark) as shown by symbols 217(A),
                     512.199(C), or 2102.03(D).  If the control
                     station is coincident with a section corner as
                     shown by symbols 229(A) or 512.101(C) also use
                     code 159 0030.  See codes 153---- through 156----
                     for the appropriate elevation code.

          150 0302   Horizontal control station, vertical angle bench
                     mark (VABM)
                     This code identifies a degenerate line placed on
                     a horizontal control station, third order or
                     better, with vertical angle elevation indicated
                     by the label VABM as shown by symbols 218(A) or
                     2102.03(D).  See codes 153---- through 156----
                     for the appropriate elevation code.

          150 0303   Horizontal control station, checked spot
                     elevation
                     This code identifies a degenerate line placed on
                     a horizontal control station, third order or
                     better, with a checked spot elevation as shown by
                     symbols 219(A), 512.99(C), or 2102.04(D).  Do not
                     code the elevation value in this category because
                     it is coded in the hypsography category.

          150 0310   Vertical control station, third order or better,
                     tablet
                     This code identifies a degenerate line that is
                     placed on a vertical control station with
                     elevation data of third order or better and that
                     is marked with a tablet as is shown by symbols
                     220(A), 512.100(C), or 2102.06(D).  If that
                     station is coincident with a found section corner
                     as shown by symbols 230(A) or 512.102(C), also
                     use code 159 0030.  See codes 153--- through 156-
                     -- for the appropriate elevation code.

          150 0311   Vertical control station, recoverable mark, third
                     order or better, no tablet
                     This code identifies a degenerate line placed on
                     a vertical control station without a tablet but
                     with a recoverable mark as shown by symbols
                     221(A), 512.100(C), or 2102.07(D).  See codes
                     153---- through 156---- for the appropriate
                     elevation code.

          150 0320   Boundary monument, third order or better, tablet
                     This code identifies a degenerate line placed on
                     a  boundary monument with elevation data of third
                     order or better that has a tablet as shown by
                     symbols 222, 501 (A) or 512.104, 523.22 (C).  If
                     the monument is shown by symbols  222(A)  or 
                     512.104(C)  also  use code 159 0009;  if  shown 
                     in  red  by  symbols  501(A)  or  523.11(C)  also 
                     use  code  159  0030.    Although  both  of 
                     these  symbols  are  digitized  in  another 
                     category,  they  must
                     be digitized in this category as well to collect
                     the elevation data.  A monument number, if shown,
                     is encoded in the Boundaries category.  See codes
                     153 ---- through 156 ---- for the appropriate
                     elevation code.

          150 0321   Boundary monument, third order or better, no
                     tablet
                     This code identifies a degenerate line placed on
                     a boundary monument with elevation data of third
                     order or better but without a tablet as shown by
                     symbols 223, 501 (A) or 512.104, 523.11 (C).  If
                     the monument is shown by symbols 223(A) or
                     512.104(C), also use code 159 0009; if shown in
                     red by symbols 501(A) or 523.11(C), also use code
                     159 0030.  A monument number, if shown, is
                     encoded in the Boundaries category.  See codes
                     153 ---- through 156 ---- for the appropriate
                     elevation code.

          150 0330   Reference monument
                     This code identifies a degenerate line placed on
                     a reference monument shown by symbols 226(A) or
                     512.105(C).

          150 0331   U.S. mineral or location monument
                     This code identifies a degenerate line placed on
                     a U.S. mineral or location monument as shown by
                     symbols 227(A), 512.106(C), or 2102.12(D).  This
                     is the only code in this category that appears on
                     1:100,000-scale maps where it is shown by symbol
                     112.46(B).

          150 0332   Other control point
                     This code identifies a degenerate line placed on
                     any other control point as shown by symbols
                     231(A) or 512.103(C).

  3.9.6   General Purpose Attribute Codes
          There are no general purpose attribute codes in this
          category.

  3.9.7   Descriptive Attribute Codes
          There are nine attribute codes that are used to encode
          fractions of elevation values in tenths.

                  150 0601   .1
                  150 0602   .2
                  150 0603   .3
                  150 0604   .4
                  150 0605   .5
                  150 0606   .6
                  150 0607   .7
                  150 0608   .8
                  150 0609   .9

  3.9.8   Parameter Attribute Codes
          151 00--   State or State equivalent FIPS code
                     Enter in the two spaces, flush right, the two
                     digit FIPS code for the state in which the
                     control point is located.

          152 0---   County or county equivalent FIPS code
                     Enter in the three spaces, flush right, the
                     three-digit FIPS code for the county in which the
                     control point is located.

          153 ----   Elevation in feet
                     Enter in the four spaces, flush right, the
                     elevation shown for the control point, shown in
                     feet on standard unit maps.  If the elevation is
                     greater than 9,999 feet use code 156 ----.

          154 ----   Elevation in meters
                     Enter in the four spaces, flush right, the
                     elevation shown for the control point, shown in
                     meters on metric unit maps.  If a fractional part
                     of a meter is shown, use the appropriate
                     descriptive attribute to encode the value.

          155 ----   Elevation in feet below datum
                     Enter in the four spaces, flush right, the
                     elevation shown for the control point.  This code
                     is only used for negative elevations shown in
                     feet on standard unit maps.

          156 ----   Elevation minus 10,000 for elevations greater
                     than 9,999 feet
                     If the elevation for a control point is greater
                     than 9,999 feet, subtract 10,000 from that
                     elevation and enter the remainder in the four
                     spaces, flush right.  Do not use this code with
                     code 153 ---- to encode the total amount.

          157 ----   Elevation in meters below datum
                     Enter in the four spaces, flush right, the
                     elevation shown for the control point.  This code
                     is only used for negative elevations shown in
                     meters on metric unit maps.


                     Examples:  elevation 8,745 feet   - 153 8745
                                elevation 12,321 feet  - 156 2321
                                elevation 423 meters   - 154 0423
                                elevation 3,480.5 feet - 153 3480, 150
                     0605
                                elevation -5 feet      - 155 0005

          159 00--   Coincident feature
                     This code is defined in section 3.3.3.




  (Current version containing all changes through 11/15/93)



  3.10    TRANSPORTATION--MAJOR CODES 170, 180, 190
          The National Mapping Division collects digital information
          about transportation in three categories to support the
          analysis and extraction of data to meet the needs of a
          wide variety of users.  The categories collected are:

               major code 170 - Roads and Trails
               major code 180 - Railroads
               major code 190 - Pipelines, Transmission Lines, and
                                Miscellaneous Transportation Features


  3.10.1  General Principles
          These data are collected in three separate categories for
          each map source, which means that the attribute codes from
          the three categories are not intermingled, however the
          three categories are distributed by the National
          Cartographic Data Base Office as one unit.  When
          collection of transportation is authorized from a map
          source, all of the transportation for that source is
          collected.  If there are no features in a particular
          category on a source, the header record shows that the
          file was initialized to hold Roads and Trails, Railroads,
          or Pipelines, Transmission Lines, and Miscellaneous
          Transportation Features, but the neatlines of the source,
          the background area, and the area outside the map, are the
          only information digitized for that category.

          The only area records in any transportation category are
          one or more background areas, existing void areas, and the
          area outside the map.

          The general purpose attribute codes that are used on
          various element types are applicable only to nodes and
          lines.  The descriptive attribute codes are used  as 
          modifiers  to  the  node,  line, degenerate line,  or 
          general  purpose  attribute  code  that  defines
          the feature.  The common attribute codes described in
          section 3.3.3 are used in this category.

          In general, if multiple attributes are needed to describe
          a feature the ordering is not significant.  An exception
          occurs in coding highway route numbers.  If a highway is
          labeled BYP, ALT, BR, and so on, then the route number
          parameter code should be preceded by the appropriate
          descriptive code for Bypass, Alternate, or Business, and
          so on.  This is especially important if multiple
          descriptive codes are required to describe a road, so that
          the descriptive code may be associated with the proper
          route number.

  3.10.1.1   Transportation
          The attribute codes authorized for use in digitizing
          Transportation are in sections 3.10.1.2 through 3.10.1.4. 
          The instructions for use of the attribute codes are in
          sections 3.10.2 through 3.10.4.

  3.10.1.2   Roads and Trails - Major Code 170

             o  Node attribute codes
                  170 0001  Bridge abutment
                  170 0002  Tunnel portal
                  170 0004  Gate
                  170 0005  Cul-de-sac
                  170 0006  Dead end
                  170 0007  Drawbridge

             o  Area attribute codes
                  000 0000  Outside area
                  170 0100  Void area

             o  Line attribute codes
                  170 0201  Primary route, class 1, symbol undivided
                  170 0202  Primary route, class 1, symbol divided by
                            centerline
                  170 0203  Primary route, class 1, divided, lanes
                            separated
                  170 0204  Primary route, class 1, one way, other
                            than divided highway
                  170 0205  Secondary route, class 2, symbol
                            undivided
                  170 0206  Secondary route, class 2, symbol divided
                            by centerline
                  170 0207  Secondary route, class 2, divided, lanes
                            separated
                  170 0208  Secondary route, class 2, one way, other
                            than divided highway
                  170 0209  Road or street, class 3
                  170 0210  Road or street, class 4
                  170 0211  Trail, class 5, other than
                            four-wheel-drive vehicle
                  170 0212  Trail, class 5, four-wheel-drive vehicle
                  170 0213  Footbridge
                  170 0214  Road ferry crossing
                  170 0215  Perimeter of parking area
                  170 0216  Arbitrary line extension
                  170 0217  Road or street, class 3, symbol divided
                            by centerline
                  170 0218  Road or street, class 3, divided, lanes
                            separated
                  170 0219  Road or street, class 4, one way
                  170 0220  Closure line
                  170 0221  Road or street, class 3, one way
                  170 0222  Road in transition
                  170 0299  Processing line

             o  Single-point attribute codes
                  None

             o  General purpose attribute codes - node or line
                  170 0401  Traffic circle
                  170 0402  Cloverleaf or interchange
                  170 0403  Tollgate, toll plaza, or perimeter of
                            toll plaza
                  170 0404  Weigh station
                  170 0405  Nonstandard section of road


             o  Descriptive attribute codes
                  170 0601  In tunnel
                  170 0602  Overpassing, on bridge
                  170 0603  Under construction, classification known
                  170 0604  Under construction, classification
                            unknown
                  170 0605  Labeled "old railroad grade"
                  170 0606  Submerged or in ford
                  170 0607  Underpassing
                  170 0609  Toll road
                  170 0610  Privately operated or restricted use
                  170 0611  Proposed
                  170 0612  Double-decked
                  170 0613  In service facility, rest area, or
                            roadside park
                  170 0614  Elevated
                  170 0615  Bypass route
                  170 0616  Alternate route
                  170 0617  Business route
                  170 0618  On drawbridge
                  170 0619  Spur
                  170 0620  Loop
                  170 0621  Connector
                  170 0622  Truck route
                  170 0623  With railroad
                  170 0624  Covered
                  170 0650  Road width 46-55 feet, 0.025 inch at
                            1:24,000
                  170 0651  Road width 56-65 feet, 0.030 inch at
                            1:24,000
                  170 0652  Road width 66-75 feet, 0.035 inch at
                            1:24,000
                  170 0653  Road width 76-85 feet, 0.040 inch at
                            1:24,000
                  170 0654  Road width 86-95 feet, 0.045 inch at
                            1:24,000
                  170 0655  Road width 96-105 feet, 0.050 inch at
                            1:24,000
                  170 0656  Road width 106-115 feet, 0.055 inch at
                            1:24,000
                  170 0657  Road width 116-125 feet, 0.060 inch at
                            1:24,000
                  170 0658  Road width 126-135 feet, 0.065 inch at
                            1:24,000
                  170 0659  Road width 136-145 feet, 0.070 inch at
                            1:24,000

             o  Parameter attribute codes
                  170 0000  Photorevised feature
                  171 ----  Number of lanes
                  172 ----  Interstate route number
                  173 ----  U.S. route number
                  174 ----  State route number
                  175 ----  Reservation, park, or military route
                            number
                  176 ----  County route

                  177 XXYY  Alphabetic portion of any route number
                            Substitute numeric equivalent of
                            alphabetic portion for XX and for YY as follows:  
                            00 = blank, 01 = A, 02 = B, 03 = C, 04 = D, 
                            05 = E, 06 = F, 07 = G, 08 = H, 09 = I, 10 = J, 
                            11 = K, 12 = L, 13 = M, 14 = N, 15 = O, 16 = P, 
                            17 = Q, 18 = R, 19 = S, 20 = T, 21 = U, 22 = V, 
                            23 = W, 24 = X, 25 = Y, 26 = Z.

                  178 0000  Best estimate of position or
                            classification
                  179 00--  Coincident feature

  3.10.1.3   Railroads - Major Code 180

             o  Node attribute codes
                  180 0001  Bridge abutment
                  180 0002  Tunnel portal
                  
                  180 0007  Drawbridge

             o  Area attribute codes
                  000 0000  Outside area
                  180 0100  Void area

             o  Line attribute codes
                  180 0201  Railroad
                  180 0202  Railroad in street or road
                  180 0204  Carline
                  180 0205  Cog railroad, incline railway, or logging
                            tram
                  180 0207  Railroad ferry crossing
                  180 0208  Railroad siding or spur
                  180 0209  Perimeter or limit of yard
                  180 0210  Arbitrary line extension
                  180 0211  Closure line
                  180 0299  Processing line

             o  Single-point attribute codes
                  None

             o  General purpose attribute codes - node, line, or
                degenerate line
                  180 0400  Railroad station, perimeter of station
                  180 0401  Turntable
                  180 0402  Roundhouse

             o  Descriptive attribute codes
                  180 0601  In tunnel
                  180 0602  Overpassing, on bridge
                  180 0603  Abandoned
                  180 0604  Dismantled
                  180 0605  Underpassing
                  180 0606  Narrow gauge
                  180 0607  In snowshed or under structure
                  180 0608  Under construction
                  180 0609  Elevated
                  180 0610  Rapid transit
                  180 0611  On drawbridge
                  180 0612  Private
                  180 0613  U.S. Government
                  180 0614  Juxtaposition

             o  Parameter attribute codes
                  180 0000  Photorevised feature
                  181 ----  Number of tracks
                  
                  
                  188 0000  Best estimate of position or classification
                  189 00--  Coincident feature

  3.10.1.4   Pipelines, Transmission Lines, and Miscellaneous
             Transportation Features - Major Code 190

             o  Node attribute codes
                  190 0001  End of transmission line at power
                            station, substation, or hydroelectric plant
                  190 0002  End of pipeline at oil or gas field
                  190 0003  End of pipeline at refinery, depot, or
                            tank farm
                  190 0004  Steel or concrete tower on transmission
                            line

             o  Area attribute codes
                  000 0000  Outside area
                  190 0100  Void area

             o  Line attribute codes
                  190 0201  Pipeline
                  190 0202  Power transmission line
                  190 0203  Telephone or telegraph line
                  190 0204  Aerial tramway, monorail, or ski lift
                  190 0205  Arbitrary line extension
                  190 0206  Closure line
                  190 0299  Processing line

             o  Single-point attribute codes
                  None

             o  General purpose attribute codes - node, line, or
                degenerate line
                  190 0400  Power station
                  190 0401  Substation
                  190 0402  Hydroelectric plant
                  190 0403  Landing strip, airport, or perimeter of
                            airport
                  190 0404  Heliport, perimeter of heliport
                  190 0405  Launch complex, perimeter of launch
                            complex
                  190 0406  Pumping station or compressor station
                  190 0407  Seaplane ramp or landing area
                  190 0408  Measuring station, or valve station

             o  Descriptive attribute codes
                  190 0600  Underground
                  190 0601  Under construction
                  190 0602  Abandoned
                  190 0603  Above ground
                  190 0604  Labeled "closed"
                  190 0605  Unimproved, loose surface
                  190 0606  Submerged
                  190 0607  Nuclear

             o  Parameter attribute codes
                  190 0000  Photorevised feature
                  
                  
                  198 0000  Best estimate of position or
                            classification
                  199 00--  Coincident feature

  3.10.2  Instructions for the Use of Attribute Codes for Roads and
          Trails

  3.10.2.1  Node Attribute Codes
          170 0001   Bridge abutment
                     This code identifies a node placed on the central
                     point of a wing tick that indicates either end of
                     a bridge.  The wing ticks are shown by symbols
                     137, 138, 146 (A); 112.83, 116.6 (B); 511.15(C);
                     or 2105.01, 2105.02 (D).

          170 0002   Tunnel portal
                     This code identifies a node placed at the point of
                     a wing tick that indicates either end of a road
                     tunnel.  The tunnel portal is indicated by symbols
                     139(A), 112.83(B), 511.17(C), or 2105.03(D).  See
                     code 170 0601 for coding the tunnel.

          170 0004   Gate
                     This code identifies a node placed on a tick line
                     labeled "gate," other than a tollgate, that
                     appears at the beginning of a controlled public
                     access road.  The feature is shown on standard
                     quadrangles by the same tick as symbols 104(A) or
                     2103.06(D) although the label is different.  This
                     code does not apply to 1:100,000-scale maps.

          170 0005   Cul-de-sac
                     This code identifies a cul-de-sac shown by symbols
                     116.10, 121.10 (B); 511.29, 516.7 (C); or
                     2103.09(D).  The symbol may be digitized as a node
                     or a line.  When a cul-de-sac is less than or
                     equal to 0.030 inch in diameter, it is digi-tized
                     as a node and assigned this code.  When the
                     feature is greater than 0.030 inch in diameter and
                     does not have an interior island, it is digitized
                     as a line.  An unattributed node is placed at the
                     end of the road, and a line is digi-tized around
                     the perimeter of the cul-de-sac and identified by
                     this code and the appropriate road classification. 
                     When the cul-de-sac is shown with an interior island,
                     the road that forms the cul-de-sac is digitized
                     and coded as appropriate for the road class and
                     is not identified by this code.

          170 0006   Dead end
                     This code identifies a dead-end street that has
                     been closed with a tick as in symbols 116(A),
                     511.21, 511.22 (C), or 2105.07(D).  This code
                     does not apply to 1:100,000-scale maps.

          170 0007   Drawbridge
                     This code identifies a node that is digitized in
                     the center of the circle portion of the
                     drawbridge symbol:  138(A), 511.15, 516.11 (C),
                     or 2105.02(D).  See code 170 0618 for coding the
                     road segments on both sides of the circle portion
                     of the drawbridge symbol.  This code does not
                     apply to 1:100,000-scale maps.

  3.10.2.2   Area Attribute Codes
          000 0000   Outside area
                     This code is described in section 3.3.3.

          170 0100   Void area
                     This code identifies an area on the source
                     material where no roads and trails data exist
                     because of replacement by imagery or a pattern
                     from another category.  A void area is also found
                     beyond the national boundary to distinguish it
                     from the background area.  Where appropriate, the
                     perimeter of the void area, usually a closure
                     line, is coded as coincident with the category
                     that defines the roads and trails void area.  The
                     closure line that defines the void area beyond
                     the national boundary is coded as coincident with
                     the Boundaries category (179 0009).

  3.10.2.3   Line Attribute Codes
          170 0201   Primary route, class 1, symbol undivided
                     This code identifies a centerline digitized along
                     a class 1 highway that has no division indicated. 
                     It is used for symbols 100, 101 (A), 121.1(B), or
                     511.10(C).  It is also used for symbol 104(A)
                     when that symbol is scribed as shown, that is,
                     without a dividing line.  It is also used for
                     symbol 2103.01(D) when labeled as an interstate
                     or U.S. Highway.  Also use the appropriate width
                     code (see codes 170 0650 through 170 0659).

          170 0202   Primary route, class 1, symbol divided by
                     centerline
                     This code identifies the centerline digitized
                     along a dual highway that is shown with three
                     road casings.  If the road exceeds the standard
                     width for the map scale, add the appropriate road
                     width code.  It is used when symbol 100(A) is
                     shown with the centerline division as is seen in
                     symbols 109(A)  or  511.11(C).    It  is  also 
                     used  for  symbol 2103.02(D) when labeled as an 
                     interstate or U.S. Highway.  This code does not 
                     apply to 1:100,000-scale maps.

          170 0203   Primary route, class 1, divided, lanes separated
                     This code describes a centerline digitized in
                     each lane of a divided highway for which the
                     lanes are separated by a median strip.  If the
                     road exceeds the standard width for the map
                     scale, add the appropriate road width code.  This
                     code is used on symbols 110(A) or 511.11(C).  The
                     code is also used on symbol 121.1(B) when the
                     road is separated into two lanes as described in
                     the remarks block of that symbol.  It is used for
                     symbol 2103.02(D) when a median strip is shown on
                     roads labeled as an Interstate or U.S. Highway.

          170 0204   Primary route, class 1, one-way, other than
                     divided highway
                     This code describes a centerline digitized in a
                     class 1 road that is designated for one-way
                     traffic by the placement of a directional arrow,
                     but is not part of a divided highway.  This
                     situation usually occurs in urban areas in which
                     major through streets may be designated as
                     one-way and are shown by symbols 100, 101 (A),
                     121.1(B), or 511.10(C).  It is also used for
                     symbol 2103.01(D) when labeled as an interstate
                     or U.S. highway and designated for one-way
                     traffic.  Although one-way streets are not
                     explicitly symbolized on 1:100,000-scale maps,
                     this code is applied to a centerline digitized in
                     a class 1 road that is clearly one-directional.

          170 0205   Secondary route, class 2, symbol undivided
                     This code describes a centerline digitized in a
                     class 2 road symbol that has no division of lanes
                     indicated.  It is used for symbols 102, 103 (A),
                     121.2(B), or 511.10(C).  This code is also used
                     for symbol 2103.01(D) when labeled
                     as a State or county highway.  (State highways
                     depicted by this symbol also require the best
                     estimate code, 178 0000.)

          170 0206   Secondary route, class 2, symbol divided by
                     centerline
                     This  code describes a centerline digitized in a
                     second class dual highway shown with three road
                     casings as in symbols 109(A) or 511.11(C).  This
                     code is also used for symbol 2103.02(D) when
                     labeled as a State or county highway. (State
                     highways depicted by this symbol also require the
                     best estimate code, 178 0000.)  This code does
                     not apply to 1:100,000-scale maps.

          170 0207   Secondary route, class 2, symbol divided, lanes
                     separated
                     This code describes a centerline digitized in
                     each lane of a class 2 highway that is shown with
                     lanes separated by a median strip as in symbols
                     110(A) or 511.11(C), but with the dashed fill as
                     in symbol 514(A).  On 1:100,000-scale maps, the
                     code identifies each lane of highway as shown in
                     symbol 121.2(B).  It is also used for symbol
                     2103.02(D) when labeled as a State or county
                     highway.  (State highways also use the best
                     estimate code, 178 0000.)

          170 0208   Secondary route, class 2, one way, other than
                     divided highway
                     This code describes a centerline digitized in a
                     class 2 highway that is designated as one way by
                     a directional arrow but is not part of a divided
                     highway.  This generally occurs only in urban
                     areas.  It is used for symbol 2130.01(D) when
                     labeled as a State or county highway and
                     designated for one-way traffic.  (State highways
                     also use the best estimate code, 178 0000.) 
                     Although one-way streets are not explicitly
                     symbolized on 1:100,000-scale maps, this code is
                     applied to a centerline digitized in a class 2
                     road that is clearly one-directional.

          170 0209   Road or street, class 3
                     This code describes a centerline digitized in a
                     class 3 road or street shown by symbols 105(A),
                     116.1(B), or 516.1(C).  It is also used for
                     symbol 2103.01(D) when unlabeled as to
                     administrative responsibility.

          170 0210   Road or street, class 4
                     This code describes a centerline digitized in a
                     class 4 road or street shown by symbols 106(A),
                     116.2(B), 516.4(C), or 2103.11(D).  This code is
                     also used for street patterns in built-up areas
                     on 1:100,000-scale maps shown by symbol 116.7(B).

          170 0211   Trail, class 5, other than four-wheel drive
                     This code describes a line digitized along a
                     class 5 trail symbol that is not designated for
                     four-wheel-drive use.  The trail symbol may be
                     labeled in various ways such as "foot trail,"
                     "pack trail," "bicycle trail," or "old railroad
                     grade." (Also see code 170 0605)  This code is
                     used for symbols 107, 133 (A), 116.3(B),
                     516.5(C), or 2103.12(D).

          170 0212   Trail, class 5, four-wheel drive
                     This code describes a line digitized along a
                     class 5 trail that is labeled "Jeep" or "4WD". 
                     It is used on symbols 107(A), 116.3(B), 516.5(C),
                     or 2103.12(D).

          170 0213   Footbridge
                     This code describes a line digitized along a
                     footbridge shown by symbols 140(A), 511.23(C), or
                     2105.04(D).  The footbridge is digitized even
                     when the connecting footpaths are not shown.  The
                     nodes that indicate the ends of the footbridge
                     are not given an attribute code.  This code does
                     not apply to 1:100,000-scale maps.

          170 0214   Road ferry crossing
                     This code describes a line digitized from bank to
                     bank along a ferry crossing route as shown in
                     symbols 150, 151 (A), 112.84(B), 511.24(C), or
                     2105.09(D).

          170 0215   Perimeter of parking area
                     This code describes a line digitized along the
                     perimeter of an area usually labeled "parking
                     area" and shown by symbol 511.25(C).  Many
                     parking areas are not labeled, but are obvious
                     because of their shape and proximity to such
                     features as retail centers and stadiums.  The
                     limits of the parking area may be shown by a road
                     symbol in which case the appropriate road code
                     classification is used as well.  If the perimeter
                     is shown by a cleared area then the apparent
                     limit of the parking area carries this code
                     alone.  This code does not apply to
                     1:100,000-scale maps.

          170 0216   Arbitrary line extension
                     This code is used on a portion of a linear
                     feature that is not symbolized, but is required
                     for connectivity of the feature, for example, a
                     line digitized to join portions of a road that is
                     broken for an underpass, as shown in symbols 145,
                     146 (A); 116.4, 116.7 (B); 516.10(C); and
                     2105.06(D).  Road classes and route numbers are
                     also encoded on this line as appropriate.

          170 0217   Road or street, class 3, symbol divided by
                     centerline
                     This code describes a centerline digitized in a
                     class 3 road or street that is shown with three
                     road casings to indicate that it is divided as is
                     shown in symbol 109(A) but without any red fill. 
                     It is also used for symbol 2103.02(D) when
                     unlabeled as to administrative responsibility. 
                     This code does not apply to 1:100,000-scale maps.

          170 0218   Road or street, class 3, divided, lanes separated
                     This code describes a centerline digitized in
                     each lane of a class 3 road or street that is
                     shown with lanes separated by a median strip as
                     in symbols 110(A) or 516.2(C), but without any
                     red fill.  It is also used for symbol 2103.02(D)
                     when unlabeled as to administrative
                     responsibility.  This code does not apply to
                     1:100,000-scale maps.

          170 0219   Road or street, class 4, one way
                     This code describes a centerline digitized in a
                     class 4 road that is designated as one way by a
                     directional arrow.  A class 4 road is shown by
                     symbols 106(A), 116.2(B), 516.4(C), or
                     2103.11(D).

          170 0220   Closure line
                     This code identifies a line segment digitized to
                     define the extent of an areal feature, such as a
                     void area, that is not otherwise explicitly
                     symbolized.

          170 0221   Road or street, class 3, one way
                     This code identifies a centerline digitized in a
                     class 3 road that is designated as one way by a
                     directional arrow.  A class 3 road is shown by
                     symbols 105(A), 116.1(B), or 516.1(C).  Use this
                     code for symbols 2103.01 and 2103.02 (D) when
                     unlabeled as to administrative responsibility and
                     designated for one-way traffic.

          170 0222   Road in transition
                     This code identifies a centerline digitized in a
                     section of any road where a change in the road
                     width occurs, and the transitional section is
                     equal to or greater than 0.25 inch in length.  An
                     unattributed node is placed at the beginning and 
                     end  of  the  extent  of  the  transitional 
                     segment.
                     The road classification is assigned to the
                     transitional segment of the road for
                     connectivity.

          170 0299   Processing line
                     Some routines in the processing software (PROSYS)
                     have limitations in the number of lines, nodes,
                     or areas that can be processed.  For example, an
                     area may be associated with no more than 4,751
                     lines.  This code describes a line or lines
                     digitized to segment the data within a file to
                     create more background areas, thereby enabling
                     large files to be processed.

  3.10.2.4  Single-Point Attribute Codes
            There are no single-point feature attribute codes in this
            category.

  3.10.2.5  General Purpose Attribute Codes - node or line
          170 0401   Traffic circle
                     This code describes the marked-off area at the
                     center of a junction of roads (three or more)
                     that forms a circle around which traffic normally
                     moves in one direction (not to be confused with
                     a cul-de-sac).  If the diameter of the interior
                     space in the circle is 0.030 inch or less the
                     feature is digitized as a node at the
                     intersection of the roads entering the circle. 
                     If the interior space is greater than 0.030 inch
                     then the feature is digitized as a center-line
                     that follows the circle and is broken by
                     unattributed nodes at the points where the roads
                     join the circle.  Road classes and route numbers
                     are also encoded on this centerline as
                     appropriate.  This code is used on symbols
                     114(A); 116.10, 121.10 (B); 511.28, 516.6 (C); or
                     2103.09(D).

          170 0402   Cloverleaf or interchange
                     This code describes an intersection of roads and
                     ramps at a cloverleaf or interchange.  If the
                     cloverleaf is shown by symbol 115(A) at the
                     symbol size shown, the feature is digitized as a
                     node and described by this code.  If the
                     cloverleaf or interchange is shown to scale, or
                     larger than symbol size as shown in symbols
                     121.5(B), 511.13, 516.8 (C), or 2103.10(D), then
                     the feature is digitized by a line that follows
                     the road and ramp pattern and is described by
                     this code.  A cloverleaf or interchange generally
                     does not carry a road class or route number.

          170 0403   Tollgate, toll plaza, or perimeter of toll plaza 
                     This code identifies a node placed at the center
                     of a tick placed on a road to identify a tollgate. 
                     It is shown by symbols 104(A), 511.26(C), or
                     2103.06(D).  It also identifies a line digitized
                     around an area on a toll road that is labeled
                     "toll plaza."  If the exact extent of the plaza is
                     difficult to determine also use code 178 0000. 
                     The centerline digitized for the road should be 
                     continued through the feature.

          170 0404   Weigh station
                     This code identifies a feature labeled "weigh
                     station" or "Agricultural Inspection Station."  On
                     1:100,000-scale maps the feature is shown by
                     symbol 121.9(B) and digitized as a line.  On
                     1:24,000-scale maps several treatments may be used
                     depending on the size of the feature.  If shown by
                     a road or ramp only, digitize a line.  If shown in
                     a similar manner to a large toll plaza, digitize
                     a line around the perimeter of the feature.  If
                     depicted by a located object symbol or building
                     without ramps or roads shown, digitize as a
                     degenerate line.

          170 0405   Nonstandard section of road
                     This code describes a line digitized on the
                     casings of a nonstandard section of any class road
                     normally symbolized by parallel road casings.  An
                     unattributed node is placed on the ends of the
                     centerline digitized on either side of the
                     nonstandard section of road, and the casings
                     delineating the nonstandard section are digitized
                     by using this code.  A road classification or
                     route number is not assigned to the lines
                     digitized as nonstandard section of road. 
                     However, for connectivity, the road classification
                     and route number  (if applicable)  are  assigned 
                     to  the  digitized  centerline  of  the  standard 
                     section  of  the  road  that
                     continues through the unattributed nodes.  This
                     description also applies to the nonstandard
                     section of the road shown at a road junction,
                     without an island, where it widens to 0.060 inch
                     or more.   When the nonstandard section of the
                     road shown by a circle (not to be confused with
                     the cul-de-sac or traffic circle) is 0.030 inch or
                     less in diameter, a node is digitized in the
                     center of the rounded section of the road and
                     assigned this code.


  3.10.2.6   Descriptive Attribute Codes
          170 0601   In tunnel
                     This code describes the portion of a road or trail
                     that is shown as being in a tunnel by symbols
                     139(A); 121.7, 116.5 (B); 511.16, 511.17, 516.12
                     (C); or 2105.03(D).  The code applies only to the
                     portion between the wing ticks (see 170 0002 for
                     coding the wing ticks).  Also use the road
                     classification code.

          170 0602   Overpassing, on bridge (except drawbridge)
                     This code describes the section of a road or trail
                     that passes over, rather than intersects, another
                     feature, such as when a road crosses over a river
                     or railroad on a bridge.  The code is applied only
                     to the section of a feature that is raised to
                     cross the obstruction.  In some cases the
                     relationship of the two features is more simply
                     shown by coding the underpassing portion (see code
                     170 0607) because only one of the two conditions
                     need be coded.  It is used with symbols 137, 138,
                     146 (A); 116.6, 121.8 (B); 511.15, 516.11 (C), or
                     2105.01, 2105.02 (D).  See code 170 0618 for
                     treatment of a feature on a drawbridge.

          170 0603   Under construction, classification known
                     This code describes the portion of a road that is
                     labelled "under construction" and the class of the
                     road is known.  It is used in conjunction with the
                     code that describes the class of the road.  The
                     code is used on symbols 112(A), 511.12(C), or
                     2103.08(D), for which the red fill indicates the
                     class of the road.  On 1:100,000-scale maps only
                     class 1 roads under construction are shown,
                     therefore, this code is used only on symbol
                     121.3(B).  The exact extent of the construction is
                     not indicated on 1:100,000-scale maps.  In such
                     cases, apply the code to all sections of the road,
                     extending from the label in both directions, until
                     an intersection with another road or the edge of an
                     urban tint provides a reasonable limit to the
                     portion of the road considered to be under
                     construction.

          170 0604   Under construction, classification unknown
                     This code describes a road labeled "under
                     construction" for which the classification is
                     unknown.  The code is used on symbols 113(A) or
                     2103.08(D).  This code is not used on
                     1:100,000-scale maps.

          170 0605   Labeled "old railroad grade"
                     This code describes a trail that follows the
                     alignment of a dismantled railroad and is labeled
                     "old railroad grade."  The code is used on symbols
                     133(A), 116.3(B), 516.5(C), or 2104.12(D), in
                     conjunction with 170 0211.  No code from the
                     railroad subcategory is used on this feature.

          170 0606   Submerged or in ford
                     This code describes the portion of a road or trail
                     that fords a stream.  The code is used on symbols
                     147, 148, 149 (A); 516.13(C); or 2105.08(D).  In
                     the case of a ford through a single-line stream,
                     the code is applied to a node placed at the point
                     where the road or trail intersects the stream. 
                     This code is not used on 1:100,000-scale maps.

          170 0607   Underpassing
                     This code describes the section of a road or trail
                     that passes under, rather than intersects, another
                     feature, as when a road crosses under another road
                     that is on an overpass.  The code is applied only
                     to the underpassing portion of a longer feature or
                     to the section of a feature that is broken to pass
                     under an obstruction.  In some cases the
                     relationship of the two features is more simply
                     shown by coding the overpassing portion (see code
                     170 0602) because only one of the two conditions need 
                     be coded.  This code is used with symbols 145(A);
                     116.4, 121.6 (B); 511.14, 516.10 (C); or 2105.06(D).

          170 0609   Toll
                     This code describes a road that is labeled "toll
                     road."  It is used on symbols 104(A), 121.1(B), or
                     2103.06(D).

          170 0610   Privately operated or restricted use
                     This code describes a road or trail that is
                     restricted, such as a road through a military
                     reservation, a road or trail through a ranch, or
                     a fire road in a forest preserve.  These roads are
                     labeled "private" or "restricted" and may have a
                     gate shown at the point where the restriction
                     begins.  This code also describes a road or trail
                     that is not labeled but is only accessible by way
                     of a road labeled "private" or "restricted."

          170 0611   Proposed
                     This code describes a road that has been planned
                     and sufficient information was available to show
                     the proposed location on the map.  Such a road is
                     shown by symbols 516(A) or 521.3(C) and is labeled
                     "proposed location."  This code is not used on
                     1:100,000-scale maps.

          170 0612   Double-decked
                     This code describes a road that is constructed
                     over another road or a road on a two-level bridge. 
                     The double-decked structure is shown by the
                     standard road symbol appropriate to its class,
                     symbol 2103.03(D), and is labeled "double-decked." 
                     This code is not used on 1:100,000-scale maps.

          170 0613   In service facility, rest area, or roadside park
                     This code identifies a road that runs through a
                     service facility or rest area.  On 1:24,000- and
                     1:25,000-scale maps the facility is labeled
                     "service facility," "service area," "service
                     plaza," "rest area" or "roadside park,"  shown by
                     symbols 511.18 or 516.9(C).  No specific symbol is
                     shown in reference A.  On 1:100,000-scale maps the
                     facility is shown by symbols 116.8(B) or 121.9(B),
                     scribed to scale.  The service facility roads are
                     usually distinguished by a different line weight
                     from that of the main road and do not require a
                     road class.

          170 0614   Elevated
                     This code describes a road that is labeled
                     "elevated" to indicate that it is raised above
                     ground level.  This code is not used on bridges.
                     (See 170 0602)

          170 0615   Bypass
                     This code describes a road that is identified as
                     a bypass route by the presence of the letters
                     "BYP" in the highway route marker.  This code is
                     used in addition to and precedes the parameter
                     code that contains the route number.

          170 0616   Alternate
                     This code describes a road that is identified as
                     an alternate route by the presence of the letters
                     "ALT" in the highway route marker.  This code is
                     used in addition to and precedes the parameter
                     code that contains the route number.

          170 0617   Business
                     This  code describes a road that is identified as
                     a business route by the presence of the letters
                     "BR" in the highway route marker.  This code is
                     used in addition to and precedes the parameter
                     code that contains the route number.

          170 0618   On drawbridge
                     This code describes a centerline digitized along
                     the portion of a road that crosses an obstruction,
                     usually a water area, on a drawbridge shown by
                     symbols 138(A) or 2105.02(D).  See code 170 0007
                     for coding the circular portion of the drawbridge
                     symbol.  This code does not apply to 1:100,000-
                     scale maps.

          170 0619   Spur
                     This code identifies a road that is described as
                     a spur route by the presence of the word "Spur" in
                     the highway route marker.  This code is used in
                     addition to and precedes the parameter code that
                     contains the route number.

          170 0620   Loop
                     This code identifies a road that is described as
                     a loop route by the presence of the word "Loop" in
                     the highway route marker.  This code is used in
                     addition to and precedes the parameter code that
                     contains the route number.

          170 0621   Connector
                     This code identifies a road that is described as
                     a connector route by the presence of the word
                     "Conn" in the highway route marker.  This code is
                     used in addition to and precedes the parameter
                     code that contains the route number.

          170 0622   Truck route
                     This code identifies a road that is described as
                     a truck route by the presence of the abbreviation
                     "TR" in the highway route marker.  This code is
                     used in addition to and precedes the parameter
                     code that contains the route number.

          170 0623   With railroad
                     This code describes a section of a road or street
                     where the railroad is superimposed on the road as
                     shown by symbols 124(A), 112.25(B), 512.08, 512.09
                     (C), or 2104.07(D).  Also use the appropriate road
                     classification code.  Because the description
                     indicates coincidence with a railroad, the
                     coincident feature code is not required.

          170 0624   Covered
                     This code describes a feature that is labeled
                     "covered."

          170 0650   Road width 46-55 feet, 0.025 inch at 1:24,000
          170 0651   Road width 56-65 feet, 0.030 inch at 1:24,000
          170 0652   Road width 66-75 feet, 0.035 inch at 1:24,000
          170 0653   Road width 76-85 feet, 0.040 inch at 1:24,000
          170 0654   Road width 86-95 feet, 0.045 inch at 1:24,000
          170 0655   Road width 96-105 feet, 0.050 inch at 1:24,000
          170 0656   Road width 106-115 feet, 0.055 inch at 1:24,000
          170 0657   Road width 116-125 feet, 0.060 inch at 1:24,000
          170 0658   Road width 126-135 feet, 0.065 inch at 1:24,000
          170 0659   Road width 136-145 feet, 0.070 inch at 1:24,000

                     The 10 codes listed above are used to describe a
                     road that is scribed to scale rather than shown by
                     the standard size symbol on 1:24,000-scale maps. 
                     This code is used in addition to the code that
                     describes the class of the road.  At
                     1:24,000-scale, roads greater than 40 feet and
                     dual highways greater than 70 feet are scribed to
                     scale.  This code does not apply to 1:100,000-
                     scale maps.


  3.10.2.7   Parameter Attribute Codes
          170 0000   Photorevised feature
                     This code is described in section 3.3.3.

          171 ----   Number of lanes
                     This code is used to encode the number of lanes
                     annotated on a road on the source map.  The number
                     of lanes is entered in the spaces, flush right,
                     one to four digits.  Use this code on all segments
                     of a road to which the annotated number of lanes
                     applies.

          172 ----   Interstate route number
                     This code is used to encode the route number of an
                     interstate highway.  Enter the number shown on the
                     highway route marker in the spaces, flush right,
                     one to four digits.  If the route number contains
                     alphabetic characters also use 177 XXYY.  If the
                     highway is labeled BYP, ALT, or BR, this parameter
                     code should be preceded by the appropriate
                     descriptive code, such as 170 0615, 170 0616, or
                     170 0617 respectively.   Do not encode the
                     uppercase "I" that is sometimes associated with an
                     interstate highway, as this parameter code imparts
                     that information.

          173 ----   U.S. route number
                     This code is used to encode the route number of a
                     U.S. highway.  Enter the number shown on the
                     highway route marker in the spaces, flush right,
                     one to four digits.  If the route number contains
                     alphabetic characters also use code 170 XXYY.  If
                     the highway is labeled BYP, ALT, or BR, this
                     parameter code, should be preceded by the
                     appropriate descriptive code, such as 170 0615,
                     170 0616, or 170 0617 respectively.  Do not encode
                     the uppercase "US" that is sometimes associated
                     with a U.S. highway, as this parameter code
                     imparts that information.

          174 ----   State route number
                     This code is used to encode the route number of a
                     State highway.  Enter the number shown on the
                     highway route marker in the spaces, flush right,
                     one to four digits.  If the route number contains
                     alphabetic characters also use code 177 XXYY.  If
                     the highway is labeled BYP, ALT, or BR, this
                     parameter code, should be preceded by the
                     appropriate descriptive code, such as 170 0615,
                     170 0616, or 170 0617 respectively.  Do not encode
                     the uppercase "SR" that is sometimes associated
                     with a State highway, as this parameter code
                     imparts that information.

          175 ----   Reservation, park, or military route number
                     This code is used to encode the route number of a
                     reservation, park, or military route number. 
                     Enter the number shown on the highway route marker
                     in the spaces, flush right, one to four digits. 
                     If the route number contains alphabetic characters
                     also use code 177 XXYY.  If the highway is labeled
                     BYP, ALT, or BR, this parameter code, should be
                     preceded by the appropriate descriptive code, such
                     as 170 0615, 170 0616, or 170 0617 respectively. 
                     This code is not used on 1:100,000-scale maps.

          176 ----   County route number
                     This code is used to encode a county route number. 
                     Enter the number shown on the highway route marker
                     in the spaces, flush right, one to four digits. 
                     If the route number contains alphabetic characters
                     also use code 177 XXYY.  If the highway is labeled
                     BYP, ALT, or BR, this parameter code should be
                     preceded by the appropriate descriptive code, such
                     as 170 0615, 170 0616, or 170 0617 respectively. 
                     This code is not used on 1:100,000-scale maps.

          177 XXYY   Alphabetic portion of any route number
                     This code is used to encode the alphabetic portion
                     of any route number.  The code is used in
                     conjunction with the appropriate code, 172 ----
                     through 176 ----, if the route designation is
                     mixed numeric and alphabetic.  The code can hold
                     one or two letters by substituting the numeric
                     equivalent 01 to 26 for the letters A to Z with 00
                     substituting for a blank.  If one letter is
                     encoded it is entered in the YY portion of the
                     code with blank coded into the XX portion.  The
                     code precedes or follows the numeric route code in
                     accordance with its actual position.  In the case
                     of an entirely alphabetic route designator, also
                     use the code to specify jurisdiction with 0000
                     entered into the minor code.

          Examples:
               State Route B143 = 177 0002 174 0143
                     County Route 6R  = 176 0006 177 0018
                     U.S. Route A1A   = 177 0001 173 0001 177 0001
                     State Route KK   = 177 1111 174 0000

                     Do not use this code to represent "ALT", "BR",
                     "BYP", "I" (interstate), "SR" (state route), or
                     "U.S." (United States) as these qualifiers of the 
                     route number are encoded by other codes.  For
                     example:  Alternate U.S. route 1 would be coded
                     170 0616 173 0001.

          178 0000   Best estimate of position or classification
                     This code is described in section 3.3.3.

          179 00--   Coincident feature
                     This code is described in section 3.3.3. One
                     example for this category is a road on a dam
                     (shown by symbols 155(A), 112.65(B), or
                     2108.04(D)) that has the code 179 0005 
                     assigned to it, in addition to the codes that
                     describe the road.

  3.10.3  Instructions for the Use of Attribute Codes for Railroads

  3.10.3.1   Node Attribute Codes
          180 0001   Bridge abutment
                     This code describes a node placed on the central
                     point of a wing tick that indicates either end of
                     a railroad bridge.  The wing ticks are shown by
                     symbols 141, 142, 143 (A); 112.17(B); 512.21(C);
                     or 2105.02, 2105.05 (D).  For any symbol in which
                     the tick is represented by two lines meeting at an
                     acute angle, the node is placed at the point.  For
                     any symbol in which the tick is represented by two
                     lines meeting a third line at obtuse angles, the
                     node is centered on the middle line.

          180 0002   Tunnel portal
                     This code identifies a node placed at the point of
                     a wing tick that indicates either end of a
                     railroad tunnel.  The tunnel portal is indicated
                     by symbols 144(A), 112.19(B), 512.21(C), or
                     2105.03(D).
                                                        
                                    
                       
                                                                      
                                                                      
                                                                      
                                                                      
                                              
          180 0007   Drawbridge
                     This code identifies a node that is digitized in
                     the center of the circle portion of the drawbridge
                     shown by symbols:  143(A), 512.21(C), or
                     2105.02(D).  See code 180 0611 for coding the
                     railroad segments on both sides of the circle
                     portion of the drawbridge symbol.  This code does
                     not apply to 1:100,000-scale maps.

  3.10.3.2   Area Attribute Codes
          000 0000   Outside area
                     This code is described in section 3.3.3.

          180 0100   Void area
                     This code identifies an area on the source
                     material where no railroad data exist because of
                     replacement by imagery or a pattern from another
                     category.  A void area is also found beyond the
                     national boundary to distinguish it from the
                     background area.  Where appropriate, the perimeter
                     of the void area, usually a closure line, is coded
                     as coincident with the category whose pattern
                     defines the void area.  The closure line that
                     defines the void area beyond the national boundary
                     is coded as coincident with the Boundaries
                     category (189 0009).

  3.10.3.3   Line Attribute Codes
          180 0201   Railroad
                     This code describes a railroad line shown by
                     symbols 117 through 123, 127 through 130 (A);
                     112.11 through 112.14 (B); 512.1 through 512.5,
                     512.10 through 512.13 (C); or 2104.01 through
                     2104.06, 2104.10, 2104.11 (D). Unless qualified by
                     a descriptive or parameter code, this code
                     indicates a single-track, standard-gauge operating
                     railroad line.  If the symbol denotes a
                     multiple-track railroad line, the centerline of
                     the symbol is digitized by using this code as well
                     as the appropriate parameter code to indicate the
                     number of tracks.

          180 0202   Railroad in street 
                     This code describes a railroad located on a
                     street.  It is shown by symbols 124(A), 112.25(B),
                     512.8, 512.9 (C), or 2104.07(D), where the street
                     symbol is superimposed on the railroad symbol. 
                     Because the definition of this code
                     indicates coincidence with a street, the
                     coincident feature code is not used in this case.

          180 0204   Carline
                     This code describes a carline shown by symbols
                     131, 132, 133 (A); 112.27(B); or 512.14, 512.15
                     (C).  If the feature is labeled as "abandoned,"
                     "dismantled," and so on, use the appropriate
                     descriptive code in addition to this code.  This
                     code does not apply to provisional edition maps.

          180 0205   Cog railroad, incline railway, or logging tram
                     This code describes a special purpose railroad
                     such as a cog railroad, incline railway, or
                     logging tram as shown by symbols 188(A),
                     112.23(B), 512.24(C), or 2110.02(D).  If the
                     feature is labeled "abandoned," "dismantled," and
                     so on, use the appropriate descriptive code in
                     addition to this code.

          180 0207   Railroad ferry crossing
                     This code describes a line digitized from bank to
                     bank along a ferry crossing route as shown in
                     symbols 150(A), 112.21(B), 512.23(C), or
                     2105.09(D).

          180 0208   Railroad siding, or spur
                     This code describes a railroad siding that is one
                     or more single tracks branching off from a main
                     line of a railroad and shown by symbols 126(A),
                     112.16(B), 512.7(C), or 2104.09(D).  This code
                     also describes a spur that is single track that
                     diverges from the main track and leads to some
                     facility such as an industrial point.  In both
                     references the siding or spur is shown with a line
                     weight of 0.003 inch to distinguish it from the
                     main line, which is shown by a line weight of
                     0.005 inch.  A railroad siding or spur may be of
                     any length.

          180 0209   Perimeter or limit of yard
                     A railroad yard as shown in symbols 125(A),
                     112.15(B), 512.6(C), or 2104.08(D) is mapped to
                     scale with the main line through the yard and the
                     outermost tracks that form the perimeter shown in
                     true position.  The rest of the tracks in the yard
                     are shown by a representative pattern.  Therefore
                     the outline of the yard is digitized as a line, by
                     following the outermost tracks, given this code. 
                     The open end of the yard is closed off by a
                     digitized line given this code and the code 180
                     0210.  The main line is digitized and described by
                     the appropriate railroad code where it can be
                     distinguished.  Large railroad yards may have
                     interior islands or clear areas, that are not
                     occupied by the track pattern.  These area limits
                     are digitized as a line by following the innermost
                     track and identified with this code.

          180 0210   Arbitrary line extension
                     This code is used on a portion of a linear feature
                     that is not symbolized; for example, this code may
                     be used to identify a line digitized to complete
                     or join portions of linear features, as in the
                     underpass shown in symbols 145(A), 512.20(C), or
                     2105.06(D).  This code is used in addition to the
                     primary code.

          180 0211   Closure line
                     This code identifies a line segment digitized to
                     define the extent of an areal feature, such as a
                     void area, that is not otherwise explicitly
                     symbolized.

          180 0299   Processing line
                     Some routines in the processing software (PROSYS)
                     have limitations on the number of lines, nodes, or
                     areas that can be processed.  For example, an area
                     may be associated with no more than 4,751 lines. 
                     This code describes the 
                     line or lines digitized to segment the data within
                     a file to create more background areas, thereby
                     enabling large files to be processed.

  3.10.3.4   Single-Point Attribute Codes
             There are no single-point attribute codes in this category.

  3.10.3.5   General Purpose Attribute Codes - node, line, or
             degenerate line
          180 0400   Railroad station, perimeter of station 
                     This code is used to describe a structure labeled
                     railroad station. If the station is shown by
                     symbols 136(A), 112.18(B), 512.18(C), or
                     2104.14(D), the station is digitized as a node on
                     the line that represents the railroad.  If the
                     structure is less than 0.030 inch and separated by
                     a gap in the line, it is digitized as a degenerate
                     line. If the station is shown to scale, then a
                     line is digitized that defines the perimeter of
                     the station and is assigned this code.

          180 0401   Turntable
                     This code is used to describe a railroad
                     turntable.  If the turntable is shown by symbols
                     134(A), 512.17(C), or 2104.13(D) and is 0.06 inch
                     in diameter, it is digitized as a node on the
                     railroad line.  If the turntable is shown to scale
                     then it is digitized as a line that defines the
                     circumference of the turntable.  This code is not
                     used on 1:100,000-scale sources.

          180 0402   Roundhouse
                     This code is used to describe a railroad
                     roundhouse as shown by symbols 135(A), 112.22(B),
                     512.16(C), or 2104.13(D).
                     Digitize a line that defines the perimeter of the
                     roundhouse and give it this code.

  3.10.3.6   Descriptive Attribute Codes
          180 0601   In tunnel
                     This code describes the portion of a railroad
                     that is shown as being in a tunnel by symbols
                     144(A), 112.19(B), 512.22(C), or 2105.03(D).  The
                     code applies only to the portion of the railroad
                     feature between the wing ticks.  The code is used
                     in addition to the codes that describe the
                     railroad type.

          180 0602   Overpassing, on bridge (except drawbridge)
                     This code describes the section of a railroad
                     that passes over, rather than intersects, another
                     feature, as when a railroad crosses over a river
                     or a road on a bridge.  The code is applied only
                     to the section of a feature that is raised to
                     cross an obstruction.  In  some cases the
                     relationship of the two features is more simply
                     shown by coding the underpassing portion (see
                     code 180 0605) because only one of the two
                     conditions need be coded.  It is used with
                     symbols 141, 142, 143 (A); 112.17(B); 512.21(C);
                     or 2105.02, 2105.05 (D).  See code 180  0611 for
                     treatment of a feature on a drawbridge.

          180 0603   Abandoned
                     This code is used to describe any railroad that
                     is labeled "abandoned."  An abandoned railroad is
                     one for which the tracks and roadbed are still in
                     place, although unused and of varying conditions. 
                     It is used with symbol 112.24(B).

          180 0604   Dismantled
                     This code describes a railroad that is labeled
                     "dismantled."  The term dismantled means that 
                     the tracks have been removed.  Many railroads that
                     are dismantled are labeled "old railroad grade"
                     and are used and symbolized as trails on the
                     Roads and Trails subcategory.  These trails are
                     not to be collected in the Railroad subcategory. 
                     Only features actually labeled "dismantled" are
                     to be collected as a railroad feature, such as
                     dismantled logging trams.

          180 0605   Underpassing
                     This code describes the section of a railroad
                     that passes under, rather than intersects,
                     another feature, as when a railroad crosses under
                     a road that is on an overpass.  The code is
                     applied only to the underpassing portion of  a
                     longer feature or to the section of a feature
                     that is broken to pass under an obstruction.  In
                     some cases the  relationship of the two features
                     is more simply shown by coding the overpassing
                     portion (see code 180 0602) because only one of
                     the two conditions need be coded.  It is used
                     with symbols 145(A), 112.20(B), 512.20(C), or
                     2105.06(D).

          180 0606   Narrow gauge
                     This code is used to describe any railroad that
                     is shown by symbols 127 through 130 (A); 112.13,
                     112.14 (B); 512.10 through 512.13 (C); or
                     2104.10, 2104.11 (D).  This code is used in
                     addition to the line code that defines the
                     feature as a railroad.

          180 0607   In snowshed or under structure
                     This code is used to describe any portion of a
                     railroad that is shown with a snowshed as in
                     symbols 177(A), 112.26(B), 512.19(C), or 2106.06
                     (D) or that is shown as running through a
                     building in the same way.  The railroad in  the 
                     snowshed  or  building  is  digitized  as  a
                     centerline in the symbol, and the building is
                     collected in the manmade features category.

          180 0608   Under construction
                     This code is used to describe any feature that is
                     labeled "under construction."

          180 0609   Elevated
                     This code is used to describe any feature that is
                     labeled "elevated."

          180 0610   Rapid transit
                     Rapid transit railroad lines are shown by the
                     standard railroad symbol appropriate to the
                     feature but, in addition, are labeled "rapid
                     transit."  This code is used to describe symbols
                     117, 120 (A); 112.11, 112.12 (B); or 2104.01,
                     2104.04 (D), when labeled "rapid transit."

          180 0611   On drawbridge
                     This code describes the portion of a railroad
                     that crosses an obstruction, usually water, on a
                     drawbridge shown by symbols 143(A), 512.21(C), or
                     2105.02(D).  This code does not apply to
                     1:100,000-scale maps.  The digitized railroad on
                     drawbridge is divided by a node placed in the
                     circular portion of the drawbridge symbol and
                     coded with code 180 0007.

          180 0612   Private
                     This code describes a railroad labeled "private."

          180 0613   U.S. Government
                     This code describes a railroad labeled as
                     belonging to the U.S. Government.

          180 0614   Juxtaposition
                     This code describes a railroad shown by symbol
                     123(A) or 2104.06(D).  The juxtaposition of
                     railroad tracks outside of a railroad yard
                     indicates that more than one railroad company
                     shares the roadbed.  Each railroad is digitized
                     as described under "Railroad" (180 0201) and this
                     code is used on  each line of the railroad
                     digitized.  On 1:100,000-scale maps a similar
                     treatment is used to indicate juxtaposition.

  3.10.3.7   Parameter Attribute Codes
          180 0000   Photorevised feature
                     This code is described in section 3.3.3.

          181 ----   Number of tracks
                     This code is used to encode the number of tracks
                     for a multiple track railroad as shown in symbols
                     121 through 123 (A); 512.3, 512.4 (B); 112.12(C);
                     or 2104.4(D).  The number of tracks is entered in
                     the spaces, flush right, one to four digits.  Use
                     this code on all segments of a railroad to which
                     the track number applies.  Do not attempt to
                     encode the number of tracks shown in railroad
                     yards.

          188 0000   Best estimate of position or classification
                     This code is described in section 3.3.3.

          189 00--   Coincident feature
                     This code is described in section 3.3.3.

  3.10.4  Instructions for the Use of Attribute Codes for Pipelines,
          Transmission Lines, and Miscellaneous Transportation
          Features

  3.10.4.1   Node Attribute Codes
          190 0001   End of transmission line at power station,
                     substation, or hydroelectric plant
                     This code describes a node placed at the end of
                     a transmission line that terminates at a power
                     station, substation, or power plant.  Do not use
                     this code when the termination point is not
                     identified.

          190 0002   End of pipeline at oil or gas field
                     This code describes a node placed at the end of
                     a pipeline that terminates at an oil or gas
                     field.  The code is used only when the area that
                     is labeled oil field or gas field is not
                     separated from the termination point by any other
                     feature.

          190 0003   End of pipeline at refinery, depot, or tank farm
                     This code describes a node placed at the end of
                     a pipeline that terminates at a labeled refinery
                     or depot.  It is also used when the pipeline
                     terminates at a group of tanks that make up a
                     tank farm, whether labeled or not.

          190 0004   Steel or concrete tower on transmission line
                     This code describes a node placed on a steel or
                     concrete tower, that is located on a transmission
                     line, shown by an open square as in symbols
                     512.91(C) and 2110.01(D).

  3.10.4.2   Area Attribute Codes
          000 0000   Outside area
                     This code is described in section 3.3.3.

          190 0100   Void area
                     This code identifies an area on the source
                     material where no miscellaneous transportation
                     data exist because of replacement by imagery or
                     a pattern from another category.  A void area is
                     also found beyond the national boundary to
                     distinguish it from the background area.  Where
                     appropriate, the perimeter of the void area,
                     usually a closure line, is coded as coincident
                     with the category whose pattern defines the void
                     area.  The closure line that defines the void
                     area beyond the national boundary is coded as
                     coincident with the Boundaries category (199
                     0009).

  3.10.4.3   Line Attribute Codes
          190 0201   Pipeline
                     This code describes a pipeline that is shown by
                     symbols 190, 191 (A); 112.57, 112.58 (B); 512.93,
                     512.94, 516.23 (C); or 2110.04(D).  When shown by
                     symbols 190(A), 512.94(C), or the first
                     illustration for 112.58(B), this code is used
                     alone.  When the pipeline is shown by symbols
                     191(A), 112.57(B), or 512.93(C), which indicates
                     that it is above ground, then use the descriptive
                     code 190 0603 in addition to this code.  When the
                     pipeline is submerged as shown in the
                     illustration for symbols 116.12(B) or 512.94,
                     516.23 (C), also use the descriptive code 190
                     0606.

          190 0202   Power transmission line
                     This code describes a power transmission line
                     that is shown by symbols 187(A), 112.55(B),
                     512.91(C), or 2110.01(D).  The steel or concrete
                     towers are digitized as attributed nodes (see
                     code 190 0004).  If an underground power line
                     is shown and labeled "underground," then use the
                     descriptive code 190 0600 in addition to this
                     code.

          190 0203   Telephone or telegraph line
                     This code is used to describe a telephone or
                     telegraph line shown by symbols 189(A),
                     112.54(B), 512.90(C), or 2110.03(D).  These
                     symbols are labeled "telephone" or "telegraph,"
                     but for coding purposes, no distinction is made
                     between telephone and telegraph lines.

          190 0204   Aerial tramway, monorail, or ski lift
                     This code describes an aerial tramway,  monorail,
                     or ski lift shown by symbols 188(A), 112.59(B),
                     512.95(C), or 2110.02(D) and labeled as to type.

          190 0205   Arbitrary line extension
                     This code describes an arbitrary line that is not
                     symbolized on the map but is digitized to link
                     component symbolized features into pipeline or
                     transmission line networks.  For example, a power
                     generating station located on the opposite side
                     of a road from its associated transmission lines
                     should be connected by a digitized line and given
                     this code.  This code is used in addition to the
                     primary code.

          190 0206   Closure line
                     This code identifies a line segment digitized to
                     define the extent of an areal feature, such as a
                     void area, that is not otherwise symbolized.

          190 0299   Processing line
                     Some routines in processing software (PROSYS)
                     have limitations on the number of lines, nodes,
                     or areas that can be processed.  For example, an
                     area may be associated
                     with no more than 4,751 lines.  This code
                     describes a line or lines digitized to segment
                     the data within a file to create more background
                     areas, thereby enabling large files to be
                     processed.

  3.10.4.4   General Purpose Attribute Codes - node, line, or
             degenerate line
          190 0400   Power station or power plant 
                     This code describes a power station that is shown
                     by a building symbol appropriate to the size of
                     the structure and labeled as a "power plant" or
                     "power station."  If the structure is less than
                     0.030 inch at its widest dimension and is joined
                     to a power transmission line, it is digitized as
                     a node at the end of the line.  If the structure
                     is less than 0.030 inch and separated by a gap
                     from the end of the power transmission line, it
                     is digitized as a degenerate line. If the
                     structure is greater than 0.030 inch in any
                     dimension, the outline of the structure is
                     digitized as a line.

          190 0401   Substation
                     This code describes a substation that is shown by
                     symbols 112.56(B), 512.92(C), or 211.13(D).  The
                     feature is labeled "substation" or "substa."  The
                     feature is digitized as a node if the symbol is
                     less than 0.030 inch and joined to the power
                     transmission line, as a degenerate line if less
                     than 0.030 inch and not joined to the power
                     transmission line, and as a line that defines the
                     perimeter of the substation if the symbol is
                     greater than 0.030 inch in any dimension.  The
                     buildings inside the complex are collected in the
                     Manmade Features category.  

          190 0402   Hydroelectric plant
                     This code is used to describe a hydroelectric
                     plant shown by a building symbol appropriate to
                     the size of the structure and labeled
                     "hydroelectric plant."  The feature is digitized
                     according to the same instructions as given
                     for code 190 0400.  

          190 0403   Landing strip, airport, or perimeter of airport
                     This code is used to describe a landing strip,
                     airport, or the perimeter of an airport.  When
                     shown by symbols 116.16(B), 516.26(C), or
                     2110.08(D) the feature is digitized by a line
                     that follows the runway pattern shown on the map.
                     If the symbol is more than 0.010 inch wide,
                     digitize the outline of the runways.  On
                     1:24,000-scale maps the extent of the airport may
                     be shown by a dashed line around the perimeter,
                     as shown in symbols 209(A) or 2107.06 (D); the
                     runways may be defined by a solid line, as shown
                     by symbol 2110.08(D); or the runways may be shown
                     by a screened area, with a solid line defining
                     the perimeter of the taxiways and aprons, as
                     shown by symbols 511.31(C) or 516.26(C). 
                     Digitize lines to define the runways, taxiways,
                     aprons, and the boundary of the airport if
                     available.  If it is not possible to distinguish
                     the runway, taxiway, or apron boundaries from
                     adjacent access roads or other features, digitize
                     the airport boundary only.  If a landing strip is
                     shown by a single line then digitize the line. 
                     Add code 190 0605 if the line is dashed to
                     indicate a loose or turf surface as shown by
                     symbol 511.30(C).  If the perimeter of the
                     airport is not clear and the runways are not
                     shown, then place a degenerate line in the
                     approximate center of the airport or landing
                     field and identify it with this code and with
                     code 198 0000.

          190 0404   Heliport, perimeter of heliport
                     This code describes a heliport facility.  A
                     heliport is shown by symbols 198, 209 (A); 112.4,
                     116.15 (B); 511.32, 511.33 (C); or 2111.16(D). 
                     When shown by symbols 198(A),
                     112.4(B), or 511.33(C), which are the located
                     object symbols, the feature is digitized as a
                     degenerate line.  If shown by symbols 209(A) or
                     116.15(B), then the feature is digitized as a
                     line that defines the perimeter of the heliport. 
                     Symbol 511.32(C) illustrates a solid line around
                     the perimeter of the facility and is digitized as
                     an area.

          190 0405   Launch complex, perimeter of launch complex
                     This code describes a feature that is labeled
                     launch complex. There is no standard symbol for
                     this feature.  If the limit of the complex is
                     discernible, digitize a line to define the
                     perimeter.  If the limit is not clearly defined,
                     digitize a degenerate line in the approximate
                     center of the facility and identify it with this
                     code and with code 198 0000.

          190 0406   Pumping station or compressor station
                     This code describes a pumping station or
                     compressor station associated with a gas or oil
                     pipeline.  If the feature is shown by a dot on
                     the pipeline, digitize a node and use this code. 
                     If the feature is shown separated from the
                     pipeline, digitize it as a degenerate line and
                     describe it with this code. If the feature is
                     shown by symbol 512.67(C), digitize a line by
                     following the perimeter of the area labeled
                     "pumping station" and give it this code.  The
                     buildings inside the complex are collected in the
                     Manmade Features category.

          190 0407   Seaplane ramp or landing area
                     This code describes a seaplane ramp or landing
                     area that is shown by a variety of treatments on
                     the 1:24,000-scale map and labeled.  The feature
                     is digitized by a centerline in a landing strip
                     or a line around the perimeter of a ramp
                     depending on the way the feature is shown.

          190 0408   Measuring station, or valve station
                     This code describes a measuring station or valve
                     station associated with a gas or oil pipeline
                     that is shown by a building symbol appropriate to
                     the size of the structure and labeled.  This
                     feature is digitized according to the same
                     instructions as given for code 190 0400.        
                                                                     
                                      
  3.10.4.5   Descriptive Attribute Codes
          190 0600   Underground
                     This code describes a feature that is labeled
                     "underground."  It is not used for a pipeline
                     that is assumed to be an underground feature.

          190 0601   Under construction
                     This code describes any feature that is labeled
                     "under construction."

          190 0602   Abandoned
                     This code describes any feature that is labeled
                     "abandoned."

          190 0603   Above ground
                     This code describes any feature that is labeled
                     "above ground."  It is not used on the features
                     that by definition are assumed to be above
                     ground.

          190 0604   Closed
                     This code describes any feature that is labeled
                     "closed."

          190 0605   Unimproved, loose surface
                     This code describes an aircraft landing strip
                     that is shown by a dashed line to indicate a
                     loose surface.  This code does not apply to
                     1:100,000-scale maps.

          190 0606   Submerged
                     This code describes a pipeline that is submerged.

          190 0607   Nuclear
                     This code describes a power plant that is labeled
                     "nuclear."

  3.10.4.6   Parameter Attribute Codes
          190 0000   Photorevised feature
                     This code is described in section 3.3.3.

          198 0000   Best estimate of position or classification
                     This code is described in section 3.3.3.

          199 00--   Coincident feature
                     This code is described in section 3.3.3.




  (Current version containing all Changes through 4/7/94)



  3.11    MANMADE FEATURES--MAJOR CODE 200

  3.11.1  General Principles
          The purpose in digitizing manmade features is to collect
          information on the cultural features not included in the
          other data categories described in this standard.  The
          information is gathered in a manner that permits the
          extraction and derivation of data to satisfy the needs of
          the various data users.

          The symbolization of the features collected in this
          category varies according to the scale of the map and the
          size of the feature.  The symbols referenced for manmade
          features are often a guide to the treatment of a structure
          shown to scale rather than a standard symbol.  At the
          beginning of the instructions for the use of each type of
          attribute code, general directions for the method of
          applying attribute codes to different feature treatments
          are given.  Any further instructions or explanations
          peculiar to a specific attribute code appears with that
          code.

  3.11.1.1   Manmade Features Attribute Codes
          The attribute codes authorized for use on manmade features
          are listed in this section.  Descriptions of the codes are
          in sections 3.11.2 through 3.11.8.

             o  Node attribute codes
                  None

             o  Area attribute codes
                  000 0000  Outside area
                  200 0100  Church complex (convent, retreat, and so
                            on)
                  200 0101  School campus (university, college, and
                            so on)
                  200 0102  Hospital complex (sanatorium, nursing
                            home, and so on)
                  200 0103  Orphanage
                  200 0104  Prison compound
                  200 0105  Trailer park

                  200 0120  Ski area
                  200 0122  Athletic field
                  200 0123  Golf course
                  200 0124  Shopping center
                  200 0125  Zoo
                  200 0126  Drive-in theater
                  200 0127  Racetrack or raceway
                  200 0128  Playground

                  200 0140  Marina
                  200 0141  Cable area

                  200 0150  Built-up area

                  200 0160  Industrial park
                  200 0161  Materials storage area
                  200 0162  Refinery or industrial plant
                  200 0163  Tailings
                  200 0164  Intricate surface area
                  200 0165  Oil sump or sludge pit
                  200 0180  Tank farm
                  200 0181  Feedlot
                  200 0182  Experimental farm
                  200 0183  Proving grounds
                  200 0184  Firing range
                  200 0190  Void area

             o  Line attribute codes
                  200 0200  Conveyor
                  200 0201  Boardwalk
                  200 0202  Wall
                  200 0203  Sea wall
                  200 0206  Fence line
                  200 0207  Flume (nonwater)
                  200 0209  Sewer line
                  200 0211  Coke ovens
                  200 0212  Recreational slide
                  200 0213  Screen (drive-in theatre)
                  200 0214  Drag strip, racetrack, or raceway
                  200 0215  Athletic track
                  200 0250  Arbitrary closure line
                  200 0299  Processing line

             o  Single-point attribute codes (degenerate line)
                  200 0300  Grave site
                  200 0301  Historical marker
                  200 0302  Mine tunnel entrance or cave
                  200 0303  Mine shaft
                  200 0304  Prospect
                  200 0305  Tower
                  200 0306  Burner/stack
                  200 0307  Drilled well
                  200 0308  Cliff dwelling
                  200 0309  Light
                  200 0310  Brick kiln
                  200 0311  Drill hole
                  200 0314  Guzzler
                  200 0315  Located object or landmark object
                  200 0316  Campsite
                  200 0317  Wind generator

             o  General purpose attribute codes (apply to nodes,
                areas, lines, or degenerate lines).
                  200 0400  Building

                  200 0402  Church
                  200 0403  School
                  200 0404  Municipal building
                  200 0405  Courthouse
                  200 0406  Post office
                  200 0407  City or townhall
                  200 0408  Hospital
                  200 0409  Prison
                  200 0410  Town, village, settlement, locality, or
                            unincorporated village
                  200 0411  Amphitheater
                  200 0412  Customs building
                  200 0420  Cemetery
                  200 0421  Sewage disposal plant
                  200 0422  Waterworks
                  200 0423  Oil reservoir
                  200 0424  Drilled well field
                  200 0425  Tank
                  200 0426  Offshore oil or gas platform
                  200 0427  Mine dump
                  200 0428  Open pit mine
                  200 0429  Quarry
                  200 0430  Strip mine
                  200 0431  Landfill
                  200 0432  Pit, unconsolidated material
                  200 0433  Radio or television facility
                  200 0434  Storage bin
                  200 0435  Levee
                  200 0436  Spoil bank
                  200 0438  Reclaimed area

                  200 0445  Fairgrounds
                  200 0446  Rodeo grounds
                  200 0447  Corral
                  200 0448  Boat ramp
                  200 0449  Campground
                  200 0450  Fort
                  200 0451  Swimming pool
                  200 0452  Archeological site, ruin, or Indian mound
                  200 0453  Recreation area, public use area
                  200 0454  Picnic area
                  200 0455  Port of entry
                  200 0456  Stadium
                  200 0465  Pile, dolphin, stump, or snag
                  200 0466  Breakwater, jetty, pier, dock, causeway,
                            or wharf
                  200 0467  Exposed wreck or wreckage
                  200 0468  Sunken wreck
                  200 0469  Drydock

             o  Descriptive attribute codes
                  200 0601  Underground
                  200 0602  Under construction
                  200 0603  Abandoned
                  200 0604  Water
                  200 0605  Oil
                  200 0606  Gas
                  200 0607  Chemical
                  200 0608  Covered
                  200 0609  Gravel
                  200 0610  Sand
                  200 0611  Clay
                  200 0612  Borrow
                  200 0613  Radio
                  200 0614  Lookout
                  200 0615  Unincorporated
                  200 0616  No population
                  200 0617  Submerged
                  200 0618  Ruin
                  200 0619  Caliche
                  200 0620  Chert
                  200 0621  Cinder
                  200 0622  Pumice
                  200 0623  Shale
                  200 0624  Scoria

             o  Parameter attribute codes
                  200 0000  Photorevised features
                  202 ----  Width in mils of feature to scale
                   
                  
                  208 0000  Best estimate of position or
                  classification
                  209 00--  Coincident feature or symbol

  3.11.2  Node Attribute Codes
          There are no attribute codes for nodes in this category.

  3.11.3  Area Attribute Codes
          Area attribute codes identify an area point digitized
          within a feature that is greater than 0.030 inch in length
          or width as depicted on the map.  Area attribute codes do
          not identify either the line that outlines the area or the
          individual features that appear within the area, such as
          buildings within a hospital complex. Individual buildings
          within the area are also digitized as appropriate to their
          size and class (see section 3.11.6).

          The determination of the extent of an area is simple when
          the outline is a special symbol, such as symbol 209(A),
          which outlines a cemetery as shown in symbols 214 or 215
          (A).  The outline may also be a symbol in another
          category, such as a road that delimits a trailer park. 
          The determination of the extent of the area is more
          difficult if the outline is formed by the omission of
          urban or woodland tint, as is done for a school complex,
          or formed by the juxtaposition of cleared areas and other
          features, as is done for tank farms or ski areas.  In such
          cases, the placement of the outline must be based on
          judgment.  The rules for coding the line that delimits an
          area are in section 3.11.4.

          000 0000   Outside area
                     This code is described in section 3.3.3.

          200 0100   Church complex (convent, retreat, and so on)
                     This code identifies an area that has a name or
                     label indicating that it is a church complex. 
                     The area contains buildings shown by symbols
                     168-170, 172-173 (A); 112.1(B); or 2106.05(D)
                     (see code 200 0402).

          200 0101      School campus (university, college, and so on)
                     This code identifies an area that has a name or
                     label indicating that it is a school campus.  The
                     area contains buildings shown by symbols 166,
                     167, 170-173 (A); 112.1(B); or 2106.04(D) (see
                     code 200 0403).

          200 0102   Hospital complex (sanitarium, nursing home, and
                     so on)
                     This code identifies an area that has a name or
                     label indicating that it is a health care
                     complex.  The area contains individual buildings
                     (see code 200 0408).

          200 0103   Orphanage
                     This code identifies a large building or complex
                     that has a name or label indicating that it is an
                     orphanage or institution housing children.  If
                     shown as a complex, the area contains individual
                     buildings (see code 200 0400).

          200 0104   Prison compound
                     This code identifies an area that has a name or
                     label indicating that it is a prison or detention
                     center.  If the area is without a defined
                     boundary, represented by a group of buildings,
                     then digitize the area and assign this code.  If
                     the area is clearly defined by military
                     reservation boundary symbols 207(A), 112.78(B),
                     512.28(C), or 2107.05(D), the boundary is
                     collected in the Boundaries category.  When the
                     area contains individual buildings, see codes 200
                     0409 and 200 0400.

          200 0105   Trailer park
                     This code identifies an area labeled as a trailer
                     park.  The outline of the trailer park may be
                     formed by a road pattern.  If so, do not encode
                     the outline as being coincident with a
                     transportation feature.  This is because the
                     digitized outline of the trailer park follows the
                     road 
                     casing, whereas the road itself has a centerline
                     digitized, so the two lines are not coincident.

          200 0120   Ski area
                     This code identifies an area determined to be a
                     ski area by the presence of ski lifts and slopes. 
                     The ski lifts are digitized in the transportation
                     category.  The area contains individual buildings
                     (see code 200 0400).

          200 0122   Athletic field
                     This code identifies an area that contains one or
                     several athletic fields that is defined by
                     symbols 209(A) or 2107.06(D).  These may include
                     and be labeled as running tracks, soccer fields,
                     football fields, baseball diamonds, and so on,
                     which are associated with a recreational area or
                     school system.  When the athletic field is
                     adjacent to a school it is shown by symbol
                     516.16(C) and is not labeled.  Digitize an area
                     enclosing the track and give it this code.  See
                     code 200 0215 for coding the tracks.

          200 0123   Golf course
                     This code identifies an area, shown by symbol
                     2111.17(D), that is labeled as a golf course or
                     country club regardless of size.  The outline of
                     this area is determined according to its
                     relationship to delimiting features, such as
                     rivers, railroads, or house omission tint and so
                     on.  Disregard woodland tint that separates the
                     fairways.  The area may contain individual
                     buildings (see code 200 0400).  If it is not
                     possible to distinguish the outline, then
                     digitize a degenerate line on the first letter of
                     the golf course label.

          200 0124   Shopping center
                     This code identifies an area in which a building
                     or group of buildings is labeled as a shopping
                     center.  The area does not include the parking
                     areas adjacent to the buildings, if shown, that
                     are collected with the Roads and Trails overlay.

          200 0125   Zoo
                     This code identifies an area that is labeled as
                     a zoo, zoological park, or wild animal park.

          200 0126   Drive-in theater
                     This code identifies an area defined by symbols
                     252(A), 512.68(C), or 2111.08(D).  The interior
                     structures are digitized and coded (see codes 200
                     0400 and 200 0213).

          200 0127   Racetrack or raceway
                     This code identifies an area labeled as a site of
                     horse races or motorized vehicle races and
                     labeled "race track" or "raceway."  The area
                     includes operator areas, stands, infields, pit
                     areas, and so on.  It does not include adjacent
                     parking areas.  This area may include interior
                     structures such as racetracks and grandstands
                     shown by symbols 116.9(B), 516.15(C), or
                     2110.10(D).  Significant interior structures are
                     digitized and coded (see codes 200 0400 and 200
                     0214).

          200 0128   Playground
                     This code identifies an area labeled
                     "playground."

          200 0140   Marina
                     This code identifies an area labeled "marina." 
                     This area is located along the shore of a
                     navigable waterway and may contain a
                     concentration of dock or pier structures (code
                     200 0466), boathouses, and other related
                     buildings (see code 200 0400).

          200 0141   Cable area
                     This code identifies an area delineated by
                     symbols 245(A), 512.143(C), or 2113.06(D) and
                     labeled as the site of underwater cable
                     placement.  The area normally is open ended and
                     requires closing by the use of two arbitrary
                     closure lines  (see code 200 0250).

          200 0150   Built-up area

                     This code has traditionally been applied to
                     areas delineated by symbols 520(A), 115.1(B),
                     515.1(C), or 2110.11(D), but the minimum
                     allowable size, density criteria, and
                     exclusions for built-up area have been
                     revised.  As a result, there may be areas on
                     the graphic that did not meet the previous
                     criteria for built-up area, but do meet the
                     revised criteria.  These areas will be
                     collected as built-up area.

                     Built-up area is defined as an area of
                     intensive use, with much of the land covered
                     by structures.  The limits of the built-up
                     area are determined by the relative
                     concentration of buildings and associated
                     intensive use areas, such as parking lots, and
                     the existence of a systematic street pattern.
                     Density of building and associated use areas
                     will vary from densely concentrated areas
                     downtown, to moderately concentrated
                     residential areas where most of the property
                     is developed.  Built-up area is collected if
                     the area is at least 30% built-up and is at
                     least 40 acres in size, and has a minimum
                     width of 660 feet.

                     Built-up area does not refer to political
                     boundaries and may include incorporated and
                     unincorporated areas as well as military
                     reservations.

                     Although built-up area limits need not be
                     fixed in relation to linear features, where
                     practical, the limits of built-up area should
                     share the edge with other linear features such
                     as streams, boundaries, roads, railroads, etc. 
                     The outline of built-up area should be
                     relatively smooth. It should not be extended
                     to include a few buildings nor to exclude a
                     few buildings when the smoothness of the edge
                     would be effected.  When the perimeter streets
                     are at least 30% developed, the built-up area
                     should be extended across the street to
                     include these buildings.

                     Housing developments where the street network
                     is complete and building development is well
                     underway, and it can be anticipated that most
                     of the development will be occupied, should be
                     collected as built-up area.

                     Narrow strips where there is only a road and
                     buildings along both sides of the road should
                     not be collected as built-up area, even if
                     they would connect an adjoining larger built-
                     up areas.  A large built-up area that is
                     separated from a smaller isolated built-up
                     area may be extended to include the smaller
                     area, if the smaller area is within 660 feet
                     of the larger built-up area.

                     Within a built-up area, areas which are less
                     than 30% developed, and are at least 80 acres
                     in size, with a minimum width of 660 feet, are
                     not collected as built-up.  In addition, if
                     canal/ditches, lake/ponds, reservoirs,
                     stream/rivers, swamp/marshes, parks, railway
                     yards, runways, air facilities, cemeteries,
                     golf courses, or exhibition grounds
                     (fairgrounds) are collected as areas within a
                     built-up area they are not also collected as
                     built-up.  All other area features collected
                     within a built-up area are also collected as
                     built-up areas.

                     See section 3.11.6 for information on which
                     buildings are collected within built-up areas.

          200 0160   Industrial park
                     See code 200 0162.

          200 0161   Materials storage area
                     See code 200 0162.

          200 0162   Refinery or industrial plant
                     This code and codes 200 0160 and 200 0161
                     identify areas labeled to indicate a particular
                     industrial feature.  On 1:24,000-scale source,
                     the area may contain buildings (see code 200
                     0400).  Do not use these codes for tank farms or
                     oil and gas fields.

          200 0163   Tailings
                     This code identifies an area of tailings shown by
                     symbols 324(A), 135.3(B), 535.4(C), or 2112.05(D)
                     and labeled.  Tailings are the discarded material
                     from ore processing or dredge operations piled in
                     irregular heaps and labeled "tailings" or "dredge
                     tailings."

          200 0164   Intricate surface area
                     This code describes an area shown by symbol
                     328(A).  This type of area may be labeled as a
                     disturbed surface.  Do not use this code if the
                     area is labeled "strip mine" (see code 200 0430)
                     or "Lava" (see code 080 0104).  This feature may
                     be added through photorevision and shown in
                     purple (see code 200 0000).

          200 0165   Oil sump or sludge pit
                     This code identifies an area shown by symbols
                     250(A), 512.86(C), or 2111.07(D) and labeled.

          200 0180   Tank farm
                     This code identifies an area labeled "tank farm"
                     that encompasses a group of tanks.  The tanks in
                     the interior of the area are digitized (see code
                     200 0425).  The tank farm outline, if not clearly
                     demarcated, is obtained by digitizing a line
                     around the outermost tanks.

          200 0181   Feedlot
                     This code identifies an enclosed area labeled
                     "feedlot," shown by symbol 2111.14(D).  The area
                     may contain individual buildings (see code 200
                     0400).

          200 0182   Experimental farm
                     This code identifies an area labeled to indicate
                     that it is an experimental farm or agricultural
                     research facility.  If the area contains
                     individual buildings, see code 200 0400.

          200 0183   Proving grounds
                     This code identifies an area labeled or named to
                     indicate that it is a proving ground or testing
                     area.  The area may contain individual buildings
                     (see code 200 0400).  The outline of the area may
                     be coincident with a military reservation
                     boundary (209 0009).

          200 0184   Firing range
                     This code identifies an area labeled or named to
                     indicate that it is a firing range, artillery
                     range, or detonation area.  The area may contain
                     individual buildings (see code 200 0400).  The
                     outline of the area may be coincident with a
                     military reservation boundary (209 0009).

          200 0190   Void area
                     This code identifies an area on the source
                     material where no manmade feature data exist
                     because of replacement by imagery or a pattern
                     from another category.  A void area is also found
                     beyond the national boundary to distinguish it
                     from the background area.  Where appropriate, the
                     perimeter of the void area, usually a closure
                     line, is coded as coincident with the category
                     that defines the manmade feature void area.  The
                     closure line that defines the void area beyond
                     the national boundary is coded as coincident with
                     the Boundaries category (209 0009).

  3.11.4  Line Attribute Codes
          Each line attribute code identifies a line segment
          digitized along a linear feature.  The feature may be
          digitized in segments as it intersects other features or
          changes in some way, such as a portion of a levee
          coincident with a boundary.  If the linear feature is
          represented by a dashed line, the digitized line does not
          replicate the dashes but is a solid line.

          For this overlay the line that forms the outline of an
          area has no assigned attribute code unless:

               o  it is coincident with a linear feature in another
                  category such as a boundary;

               o  the outline is so difficult to determine that it
                  warrants the use of parameter code 208 0000 to
                  indicate the uncertainty of position;

               o  it has been arbitrarily placed to close off a
                  labeled or named area that is not otherwise
                  symbolized, or to complete the closure of a feature
                  partially outlined by a line existing on the source
                  (code 200 0250); or

               o  it is a linear feature in itself, distinct from the
                  area it outlines.

          200 0200   Conveyor
                     This code identifies a line labeled "conveyor" or
                     "conveyor belt" and represented by a dashed line
                     on the 1:24,000-scale maps.  The dash length and
                     lineweight varies among map sheets.  The label
                     might have been omitted on a photorevised
                     conveyor, in which case the conveyor may still be
                     identifiable if it connects a mine or strip mine
                     to a type of plant.

          200 0201   Boardwalk
                     This code identifies a centerline digitized in a
                     boardwalk shown by symbols 254(A), 512.71(C), or
                     2111.09(D) and labeled "boardwalk." If shown to
                     scale (greater than 0.020 inch), also use code
                     202 0--- to encode the width.

          200 0202   Wall
                     This code identifies a line that represents a
                     wall as shown by symbols 192, 193 (A); 512.63,
                     512.64 (C); or 2110.06, 2110.06 (D) and labeled. 
                     If the wall is shown to scale (0.017 inch or
                     greater), digitize a centerline and also use code
                     202 0--- to encode the width.  This code is also
                     used for miscellaneous wall structures, such as
                     stabilizing walls, that are depicted on the
                     graphic source but unlabeled.

          200 0203   Sea wall
                     This code identifies a line shown by symbols
                     159(A), 112.69(B), 512.48(C), or 2108.07(D) and
                     labeled.  A sea wall is usually coincident with
                     the shoreline (see code 209 0005).

          200 0206   Fence line
                     This code identifies a line shown by symbols
                     522(A), 523.15(C), or 2110.07(D).

          200 0207   Flume (nonwater)
                     This code identifies a line shown by symbol
                     191(A) or 2110.04(D) and labeled.  An appropriate
                     descriptive code is also used to describe the
                     substance being carried by the flume, for
                     example, 200 0605 for oil flume.  Water flumes
                     are digitized as part of the hydrography data
                     category.

          200 0209   Sewer line
                     This code identifies a line shown by symbols
                     116.13(B) or 516.24(C).  Because the feature is
                     submerged, also use code 200 0617.

          200 0211   Coke ovens
                     This code identifies a centerline digitized along
                     symbols 253(A) or 512.70(C).

          200 0212   Recreational slide
                     This code identifies a line shown by symbols
                     188(A), 112.59(B), 512.117(C), or 2110.09(D).  A
                     recreational slide is shown on newer maps when it
                     is a permanent installation.

          200 0213   Screen (drive-in theater)
                     This code identifies the line within the drive-in
                     theater, shown by symbols 252(A), 512.68(C), or
                     2111.08(D) that represents the screen.

          200 0214   Drag strip, racetrack, or raceway
                     This code identifies a racetrack or raceway shown
                     by symbols 116.9(B), 516.15(C), or 2110.08(D) and
                     labeled.  See code 200 0127 to code the
                     surrounding area.  This code also identifies a
                     drag strip that is usually shown by a  straight
                     segment of road and labeled.

          200 0215   Athletic track
                     This code identifies a feature shown by symbol
                     516.16(C) that is used for track and field
                     athletic events.  The track is not named or
                     labeled when it is shown adjacent to a school or
                     other facility.  See code 200 0122 to code the
                     surrounding area.

          200 0250   Arbitrary closure line
                     This code identifies a line digitized to close
                     off an area that is partially outlined by a line
                     existing on the source.  For example, a drive-in
                     theater may have a portion of the normal symbol
                     outline overprinted by another feature.  This
                     code is used on the line digitized to close off
                     the open end.  This code also identifies a line
                     digitized to close off a labeled or named area
                     that is not otherwise symbolized on the existing
                     source, e.g., town, village, and so on.  This
                     code is used on the line digitized to delimit the
                     area.  Also use the primary code when
                     appropriate.

          200 0299   Processing line
                     Some routines in the processing system (PROSYS)
                     have limitations on the number of lines, nodes,
                     and areas that can be processed.  For example, an
                     area may be associated with no more than 4,751
                     lines.  This code describes a line or lines
                     digitized to segment the data within a file to
                     create more background areas, thereby enabling
                     large files to be processed.

  3.11.5  Single-Point Attribute Codes  (degenerate lines)
          A single-point attribute code identifies a degenerate line
          digitized on a standard USGS symbol.  The features
          identified by these codes are of a size that are
          represented by a point symbol rather than shown to scale. 
          Unless otherwise specified, the degenerate line is placed
          in the center of the symbol being digitized.

          200 0300   Grave site
                     This code identifies the location of one or two
                     graves shown by a cross and labeled "grave" as in
                     symbols 213(A), 512.119(C), or 2107.07(D).  The
                     degenerate line is digitized at the intersection
                     of the cross.  It differs from cemetery
                     symbolization by having no boundary.  See code
                     200 0420 for larger cemeteries.

          200 0301   Historical marker
                     This code identifies a feature shown by symbols
                     198(A) or 2111.03(D) (located object) or 112.4(B)
                     (landmark object) and named or labeled.  These
                     symbols are used for other landmark features so
                     the label is the distinguishing feature.

          200 0302   Mine tunnel entrance or cave
                     This code identifies a feature shown by symbols
                     184(A), 112.35(B), 512.80(C), or 2109.03(D).  The
                     degenerate line is digitized at the intersection
                     of the arms of the symbol.                      
                                                                     
                       

          200 0303   Mine shaft
                     This code identifies a feature shown by symbols
                     186(A), 112.36(B), 512.81(C), or 2109.05(D).

          200 0304   Prospect
                     The code identifies a prospect shown by symbols
                     185(A), 512.82(C), or 2109.04(D).  A prospect is
                     an excavation for the purpose of mineral
                     exploration that is smaller than a mine tunnel or
                     shaft.  A degenerate line is digitized on the
                     intersection of the arms of the symbol.

          200 0305   Tower
                     This code identifies a feature shown by symbols
                     198(A), 112.4(B), or 2111.03(D).  These symbols
                     are used for other landmark features, so the
                     label is the distinguishing feature.  If the
                     label specifies the type of tower (radio or
                     lookout) also use the appropriate descriptive
                     code (200 0613 or 200 0614).

          200 0306   Burner/stack
                     This code identifies a feature shown by symbols
                     198(A) or 2111.03(D), which is labeled as a
                     burner or stack.  The symbol is used for other
                     landmark features so the label is the
                     distinguishing feature.

          200 0307   Drilled well
                     This code identifies a feature shown by symbols
                     194(A), 112.101(B), 512.83(C), or 2111.01(D) and
                     labeled as an oil or gas well.  Also use codes
                     200 0605 (oil) or 200 0606 (gas) to specify the
                     type of well.  Only offshore wells are symbolized
                     on 1:100,000-scale sources and are shown as
                     platforms (see code 200 0426).  This code does
                     not apply to water wells, which are digitized in
                     the hydrography category.

          200 0308   Cliff dwelling
                     This code identifies a feature shown by symbols
                     182(A), 112.34(B), 512.79(C), or 2106.10(D) and
                     named or labeled.

          200 0309   Light
                     This code identifies a feature shown by symbols
                     198(A), 112.102(B), 512.163(C), or 2111.15(D) and
                     labeled "Light."

          200 0310   Brick kiln
                     This code identifies a feature shown by a circle
                     0.030 inches in diameter that is labeled "brick
                     kiln."

          200 0311   Drill hole
                     This code identifies a feature shown by symbols
                     198(A), 112.101(B), or 2111.03(D) and labeled
                     "drill hole."

          200 0314   Guzzler
                     This code identifies a feature shown by symbols
                     198(A), or 2111.03(D) and labeled "guzzler."

          200 0315   Located object or landmark object
                     This code identifies a feature shown by symbols
                     198(A), 112.4(B), 512.72(C), or 2111.03(D) and
                     NOT labeled.

          200 0316   Campsite
                     This code identifies a feature shown by symbol
                     512.72(C) and labeled.

          200 0317   Wind generator
                     This code identifies a feature shown by the
                     windmill symbol 199(A), 112.3(B), 512.69(C), or
                     2111.04(D), and labeled "wind generator."

  3.11.6  General Purpose Attribute Codes
          A building shown by a minimum size symbol, or a building
          less than 100 feet along the longest axis, is collected
          as a single-point feature (degenerate line).  A building
          that is 100 feet or more along the longest axis is
          collected as an area.  The outline of the area is treated
          in accordance with the directions given in the
          introduction of section 3.11.3.

          Within a built-up area (200 0150), collect only buildings
          that are at least 400,000 square feet, or can be
          described as an arena, auditorium, armory, capitol, city
          hall (200 0406), community center, courthouse (200 0405),
          firehouse (200 0404), hospital (200 0408), house of
          worship (200 0402), library, medical center (200 0408),
          memorial, museum, post office (200 0406), railroad
          station, school (200 0403), stadium, or town hall (200
          0407).  Note that specific codes do not exist for all of
          these building types; in these cases the building code
          (200 0400) is used.  Also note that railroad station is
          collected in the Pipelines, Transmission Lines, and
          Miscellaneous Transportation Features category.

          Outside built-up area, collect all buildings according to
          codes that follow.
 
          A building that is shown with a purple photorevised
          addition is digitized as two separate buildings. 
          The original portion of the structure is identified
          with the appropriate codes.  The purple portion is
          identified by the same codes and is, in addition,
          assigned code 200 0000 (photorevised feature).

          200 0400   Building
                     This code is used for all buildings that were
                     previously attributed as class 1 or class 2.  All
                     buildings shown by symbols 163, 164, 165 (A);
                     112.1(B); 512.52, 512.53 (C); or 2106.01 through
                     2106.03 (D); and buildings shown by old
                     symbols 175, 176 (A) or 512.57, 512.58 (C) are
                     given this attribute code.  This code is not used
                     on buildings that have a specific code, such as
                     church or hospital.  It is used, however, on
                     buildings that in themselves have no other
                     specific code but are located within a coded
                     area.  One example is a building within a prison
                     compound (see code 200 0409).  

          200 0402   Church
                     This code identifies a building shown by symbols
                     168-170, 172 (A), 512.55(C), or 2106.05(D).  This
                     code is also used on buildings shown by these
                     symbols that are located within an area coded as
                     a church complex (see code 200 0100).

          200 0403   School
                     This code identifies a building shown by symbols
                     166-167, 170-173 (A); 512.54, 512.56 (C); or
                     2106.04(D).  This code is also used on buildings
                     shown by these symbols that are located within an
                     area coded as a school complex (see code 200
                     0101).

          200 0404   Municipal building
                     This code identifies a government building shown
                     within an urban area by the building symbol,
                     other than a courthouse, post office, city, or
                     townhall.  Examples of municipal buildings are
                     fire stations, police stations, or city animal
                     pounds.

          200 0405   Courthouse
                     This code identifies a building labeled as a
                     courthouse, regardless of jurisdiction.

          200 0406   Post office
                     This code identifies a building labeled as a post
                     office.

          200 0407   City or townhall
                     This code identifies a building labeled as a city
                     or townhall.

          200 0408   Hospital
                     This code identifies a building labeled as a
                     hospital.  The code is used on all buildings
                     within an area coded as a hospital complex (200
                     0102).

          200 0409   Prison
                     This code identifies a building labeled as a
                     prison.  The code is used on the largest
                     buildings within an area labeled as a prison
                     compound.  All other buildings are coded 200
                     0400.

          200 0410   Town, village, settlement, locality, or
                     unincorporated 
                     village
                     This code identifies a location designated, by a
                     label or name, as a site of habitation by groups
                     of humans.  The localities that have a definite
                     symbolized boundary are represented in the
                     Boundaries category.  This code is intended to
                     identify unincorporated villages that on the
                     1:24,000-scale sources have no boundaries shown,
                     as well as towns, villages, and settlements that
                     on the 1:100,000-scale sources are represented by
                     a dot, street pattern, or road intersection.

                     When groups of buildings or street patterns
                     represent the locality, digitize a line depicting
                     the limits of the area, which includes the name
                     or label and related buildings and streets (see
                     code 200 0250).  When the symbol 112.42(B)
                     represents the locality, digitize a degenerate
                     line on the dot and identify it with this code. 
                     If the locality is shown by a road intersection,
                     digitize a degenerate line at the intersection
                     and identify it with this code.  If a locality is
                     named for a point feature appearing on the map,
                     and there are no other features, e.g., buildings,
                     digitize a degenerate line on the symbol. 
                     However, if the symbol does not appear on the
                     map, then digitize a degenerate line near the
                     name.  In addition, if the locality is labeled as
                     unincorporated, also use code 200 0615; if
                     unpopulated, use code 200 0616.

          200 0411   Amphitheater
                     This code identifies a structure generally
                     symbolized by a 0.003-inch solid outline that is
                     compiled to scale and labeled.

          200 0412   Customs building
                     This code identifies a building shown by symbols
                     163, 165 (A); 112.1(B); 512.52, 512.53 (C); or
                     2106.01 through 2106.03 (D) and labeled.

          200 0420   Cemetery
                     This code describes a burial site of more than
                     two graves with a delineated boundary that is
                     shown by symbols 213, 214, 215 (A); 112.72,
                     112.73 (B); 512.120, 512.121 (C); or 2107.07,
                     2107.08 (D).  If the symbol is 0.030 inch or less
                     on the longest side, digitize a degenerate line
                     on the symbol and identify it with this code. If
                     the symbol size is greater than 0.030 inch on the
                     longest side, then digitize the cemetery as an
                     area.  Because the outline of national cemeteries
                     is shown by boundary symbols 202(A), 112.74(B),
                     512.123(C), or 2107.01 (D), also assign the
                     coincident feature code 209 0009 to the outline
                     of a national cemetery.

          200 0421   Sewage disposal plant
                     This code identifies the prominent building
                     associated with a labeled sewage disposal
                     facility.  The sewage disposal ponds and
                     filtration beds are digitized in the Hydrography
                     category.

          200 0422   Waterworks
                     This code identifies the prominent building
                     associated with a labeled waterworks or water
                     treatment plant.  Any reservoirs or ponds are
                     digitized in the Hydrography category.

          200 0423   Oil reservoir
                     This code identifies a feature shown by symbols
                     251(A) or 512.87(C).  If the symbol diameter is
                     0.030 inch or less, digitize a degenerate line in
                     the center of the symbol.  If the diameter is
                     greater than 0.030 inch, digitize the feature as
                     an area.

          200 0424   Drilled well field
                     This code identifies an area of drilled oil or
                     gas wells.  It is labeled "oil field" or "gas
                     field," or "oil and gas field."  On
                     1:24,000-scale maps it contains numerous wells as
                     shown by symbols 194(A), 512.83(C), or
                     2111.01(D).  On 1:100,000-scale maps the name or
                     label is shown in the location.  When it is
                     possible to determine the extent of the oil or
                     gas field, digitize it as an area.  If the extent
                     cannot be determined, or if the source is a
                     1:100,000-scale map that only has a label, then
                     digitize a degenerate line on the first letter of
                     the label.  Also use the appropriate descriptive
                     code to specify oil or gas or both (see codes 200
                     0605 and 200 0606).

          200 0425   Tank
                     This code describes tanks shown by symbols
                     196(A), 112.2(B), 512.65(C), or 2111.02(D); or
                     shown by old symbols 197(A) or 512.66(C).  Any
                     tank 0.030 inch or less in diameter is digitized
                     as a degenerate line.  Any tank greater than
                     0.030 inch in diameter is digitized as an area. 
                     Also use the appropriate descriptive code to
                     specify the contents (see codes 200 0604 through
                     200 0607).

          200 0426   Oil or gas platform
                     This code describes an offshore oil or gas
                     platform shown by symbols 116.11(B) or 516.22(C). 
                     It is labeled "oil platform," "gas platform," or
                     "oil and gas platform."  If
                     the square is 0.030 inches or less, digitize a
                     degenerate line on the symbol.  If the symbol is
                     greater than 0.030 inches, digitize it as an
                     area.  Also use the appropriate descriptive code
                     to specify oil or gas, or both (see codes 200
                     0605 and 200 0606).

          200 0427   Mine dump
                     This code identifies a mine dump, which is a pile
                     of waste rock, from a mine.  It is shown by a
                     variety of treatments all of which are labeled
                     "mine dump."

                     When the mine dump is shown by symbols 327(A) or
                     532.23(C) digitize a centerline in the symbol
                     from one end to the other, at right angles to the
                     tick marks.  When the mine dump is large and has
                     a regular hill-like shape, it may be shown by
                     contours only, and is digitized as an area. 
                     Outline the area, but do not digitize the
                     contours.  This applies to 1:24,000-scale maps.

                     A large mine dump of an irregular shape covering
                     a large area that may not be evident from the
                     contours is overprinted with the intricate
                     surface pattern as shown by symbols 328(A) or
                     535.4(C).  Digitize an area outlined by the edge
                     of the pattern.  This applies to 1:24,000-scale
                     maps.

                     On Provisional Edition Maps all mine dumps are
                     shown by symbol 2112.05(D) and labeled.

                     On 1:100,000-scale maps all mine dumps are shown
                     by symbol 135.3(B).  This symbol is digitized as
                     an area and is distinguished from other disturbed
                     surfaces only by the label.

          200 0428   Open pit mine
                     This code describes an open pit mine, which may
                     be shown by a variety of treatments all of which
                     are labeled "open pit mine."  When the open pit
                     mine is shown only by the crossed-pick symbols
                     183(A), 112.37(B), 512.84(C), or 2109.01(D)
                     (without tint), digitize a degenerate line at the
                     intersection of the symbol.  When an open pit
                     mine is shown by symbols 333(A), 535.3(C), or
                     2112.08(D) digitize as an area.  The outline of
                     the area is formed by digitizing a centerline
                     through the brown hachures of symbol 333(A) or
                     along the edge of the brown tint of symbol
                     512.84(C).  This applies to 1:24,000-scale maps.

                     On 1:24,000-scale maps, there are large open pit
                     mines that are shown entirely by contouring and
                     a label.  These may have structures, water
                     bodies, roads, and railroads inside the pit. 
                     This feature treatment is digitized as an area. 
                     The outline of the area is the outermost contour
                     line of the pit.

                     On Provisional Edition Maps all open pit mines
                     are shown by symbol 2112.08(D) and labeled.

                     On 1:100,000-scale maps, large open pit mines are
                     shown by symbol 135.2(B) and labeled.  This
                     symbol is digitized as an area by following the
                     edge of the pattern.

          200 0429   Quarry
                     A quarry is an open pit from which rock or stone
                     is excavated.  It is shown by the same symbology
                     as the open pit mine but is labeled "quarry." 
                     The feature is digitized in the same manner as
                     described in the instructions for code 200 0428.

          200 0430   Strip mine
                     A strip mine is a shallow surface excavation that
                     may be digitized in one of two ways, which
                     depends on the symbolization shown on the source. 
                     When a linear strip mine is shown by a narrow
                     strip of disturbed surface, 0.030 inch or less in
                     width, between two contour lines as shown in
                     symbols 326(A), 535.2(C), or 2112.06(D) digitize
                     centerline of the pattern.

                     If the strip of disturbed surface is greater than
                     0.030 inch, digitize it as an area.  Digitize the
                     contour line as the outline of the strip mine.

                     When the strip mine is shown by symbols 325(A),
                     135.1(B), 535.1(C), or 2112.06(D) digitize an
                     area.  The outline of the area is the edge of the
                     disturbed surface pattern or tint.

          200 0431   Landfill
                     This code describes a feature shown by the symbol
                     328(A) that is labeled "landfill."  If the area
                     of the landfill is 0.030 inch or less in
                     diameter, digitize it as a degenerate line.  If
                     the area is greater than 0.030 inches in
                     diameter, digitize the area.  The outline of the
                     area is the edge of the disturbed surface
                     pattern.

          200 0432   Pit, unconsolidated material
                     A pit is an excavation of unconsolidated
                     materials such as  sand, gravel, or clay.  It is
                     also called a borrow pit when earth was removed
                     for construction purposes.  It is shown by
                     symbols 333(A), 112.38, 135.4 (B), 535.5(C), or
                     2112.08(D) with a crossed shovel instead of a
                     crossed pick.  When the pit is shown by symbols
                     255(A), 112.38(B), 512.85(C), or 2109.02(D)
                     without the brown tint, then
                     digitize a degenerate line at the intersection of
                     the crossed shovels.

                     When the pit is shown by symbols 333(A),
                     112.38(B), 512.85(C), or 2112.08(D) with tint,
                     digitize it as an area.  Digitize a centerline
                     through the brown hachures of symbol 333(A) or a
                     line along the edge of the brown tint pattern of
                     symbols 112.38(B) or 512.85(C).

                     For all cases, also use the appropriate
                     descriptive code to describe the specific type of
                     pit.


          200 0433   Radio or television facility
                     This code identifies a feature labeled as a radio
                     facility.  The facility may be one or more
                     buildings.  Digitize the buildings according to
                     the instructions for code 200 0400 and identify
                     each with this code.  Do not use this code for a
                     radio tower (see code 200 0305).

          200 0434   Storage bin
                     Storage bins may be symbolized as tanks or as
                     buildings, but with the label "storage bin" or
                     "silo."  Digitize the storage bin according to
                     the instructions for code 200 0425 or 200 0400,
                     as appropriate, and identify with this code.

          200 0435   Levee, dike
                     This code identifies a line shown by symbols 314
                     through 315(A); 132.13(B); 532.9, 532.11, 532.12
                     (C); or 2112.01, 2112.02 (D) or an area shown by
                     contours that may or may not be labeled.  When
                     the linear symbols are used, digitize a line and
                     identify it with this code.  When shown by
                     contours, digitize an area and identify it with
                     this code.  The perimeter of an areal feature are
                     digitized as an arbitrary closure line (200 0250)
                     because the limit is not explicitly symbolized. 
                     When the levee is shown by symbols 315(A),
                     532.12(C) or 2112.02(D), the centerline is
                     digitized along the road or railroad and is also
                     coded with feature codes 209 0017 or 209 0018 to
                     indicate coincidence.  On the 1:100,000-scale
                     sources a levee carrying a road or railroad is
                     not shown; instead the road or railroad is
                     labeled "road on levee" or "railroad on levee." 
                     For these cases digitize the centerline of the
                     road or the railroad and also use the coincident
                     feature codes 209 0017 or 209 0018.

          200 0436   Spoil bank
                     This code identifies a feature generally shown by
                     symbols 332(A), 532.13(C), or 2112.01(D).  A
                     spoil bank is a linear accumulation of dredged
                     material commonly associated with a ditch or
                     dredge tailings.  The digitized line is not
                     broken where the spaces in the symbol occur.  A
                     large spoil bank may be shown by contours and
                     labeled.  This is digitized as an area.

          200 0438   Reclaimed area
                     This code describes an area, bounded by  dashed
                     purple lines, which contains contours overprinted
                     with symbol 328(A) and labeled "reclaimed area." 
                     If the area is not labeled, a note is added to
                     the legend of the map that identifies the area as
                     "reclaimed mining."  This code also identifies an
                     area represented by a 4% purple tint and labeled
                     "reclaimed strip mine."   Digitize an
                     unattributed solid line by following the dashed
                     outline or edge of the pattern and assign this
                     code to the area.

          200 0445   Fairgrounds
                     This code describes a feature that is labeled as
                     fairgrounds or parade grounds, whether State,
                     county, or local.  The fairgrounds is digitized
                     as an area if the outline can be determined.  If
                     it is not possible to distinguish the outline,
                     then digitize a degenerate line on the first
                     letter of the fairgrounds label.

          200 0446   Rodeo grounds
                     This code describes a feature that is labeled as
                     rodeo grounds.  It is digitized as an area if the
                     outline can be determined.  If it is not possible
                     to distinguish the outline, then digitize a
                     degenerate line on the first letter of the rodeo
                     grounds label.

          200 0447   Corral
                     A corral is a fenced animal enclosure shown by
                     symbols 258(A) or 112.44(B).  When shown by
                     symbol 258, digitize the feature as an area. 
                     When shown by symbol 112.44, digitize the feature
                     as a degenerate line.

          200 0448   Boat ramp
                     A boat ramp is shown to scale in all cases.  It
                     may be any shape and size and, therefore, is
                     digitized according to the following general
                     instructions.  A boat ramp shown by a symbol of
                     0.030 inch or less on the longest side is
                     digitized as a degenerate line.  A boat ramp
                     shown by a single  line  as  in  symbol 
                     516.14(C)  is  digitized  as
                     a line.  A boat ramp shown by a symbol greater
                     than 0.030 inch on the longest side is digitized
                     as an area.

          200 0449   Campground
                     This code identifies a feature shown by symbols
                     257(A), 112.48(B), 512.115, or 2111.11(D) and
                     labeled.  If the outline of a campground can be
                     determined, digitize it as an area.  If the
                     outline cannot be determined, digitize a
                     degenerate line in the center of the base of the
                     tepee symbol.

          200 0450   Fort
                     A fort is a building or complex named or labeled
                     to indicate that it is a fort.  If the fort is
                     without a defined boundary, represented by a
                     group of buildings, and the outline can be
                     inferred, it is digitized as an area and assigned
                     this code.  If the fort is a clearly defined
                     complex, with a military reservation boundary
                     shown by symbols 207(A), 112.78(B), 512.128(C),
                     or 2107.06(D) defining the area, the area and
                     boundary are collected in the Boundaries
                     category.  Digitize any interior structures as
                     appropriate for their class.  If the fort is
                     shown as an individual building, follow the
                     general instructions for the digitizing of
                     structures and give the feature this code. 
                     Historic forts may be shown by the located object
                     symbols, 198(A), 112.4(B), or 2111.03(D).  In
                     this case, digitize a degenerate line on the
                     symbol.

          200 0451   Swimming pool
                     This code identifies a feature shown by symbols
                     179(A), 512.60, 545.4 (C), or 2205.01(D); labeled
                     "swimming pool" on earlier map editions.  On
                     later editions, this symbol is not labeled but
                     bears a resemblance to a reservoir.  If the
                     symbol is 0.030 inch or less on the longest side,
                     digitize
                     a degenerate line on the center of the symbol. 
                     If the symbol is greater than 0.030 inch on the
                     longest side, digitize it as an area. If this
                     symbol is not labeled, also use code 208 0000
                     (best estimate).

          200 0452   Archeological site, ruin, or Indian mound
                     This code describes a structure of historical
                     significance, protected by Federal or State
                     agencies, shown by symbols 181(A), 112.33(B),
                     512.78(C), or 2106.09(D).  If the symbol is 0.030
                     inch or less on a side, digitize a degenerate
                     line in the center of the symbol.  If the symbol
                     is greater than 0.030 inch on a side, digitize it
                     as an area.  Note that the outline of the symbol
                     is solid rather than dashed if the symbol is less
                     than 0.050 by 0.050 inch in size (both in
                     reference A and reference B).  This code also
                     describes an Indian mound that is shown by
                     contours and a name or label.  An unattributed
                     line is digitized to define the perimeter of the
                     area, by following the contour shown as the base
                     of the mound.  If the area defined is 0.030 inch
                     or less in diameter, digitize a degenerate line
                     inside the contour shown as the top of the mound.

          200 0453   Recreation area, public use area
                     This code identifies a feature labeled as a
                     recreation or public use area, other than
                     National or State areas that are identified in
                     the Boundaries category (section 3.8).  This
                     includes roadside parks and viewpoints, vantage
                     points, and overlooks.

                     If the outline of the recreation area can be
                     determined, digitize it as an area.  Digitize any
                     structures within the area as appropriate.  If
                     the outline of the area cannot be 
                     determined, digitize a degenerate line on the
                     first letter of the name or label that identifies
                     the recreation area.

          200 0454   Picnic area
                     This code identifies a feature shown by symbols
                     256(A), 112.47(B), 512.116(C), or 2111.10(D).  If
                     the outline of the picnic area can be determined,
                     digitize the feature as an area.  If the outline
                     cannot be determined, digitize a degenerate line
                     on the center of the picnic table symbols.

          200 0455   Port of entry
                     A port of entry is a building located at a point
                     of entry on the national boundary, shown by
                     symbol 112.43(B).  Digitize the structure
                     according to the instructions for buildings (see
                     code 200 0400).

          200 0456   Stadium
                     This code identifies a sports stadium that is not
                     associated with a school.  The classification
                     does not include parking lots or other structures
                     adjacent to the stadium.  Digitize stadiums shown
                     by symbol 112.8(B) to scale and apply this code
                     to the area.  No symbol is shown for a stadium in
                     reference A, rather the structure is shown as a
                     building and labeled.  In such cases digitize the
                     building as an area and give it this code.

          200 0465   Pile, dolphin, stump, or snag
                     This code identifies a feature shown by symbol
                     235(A).  When the feature is shown by the single
                     circle, digitize a degenerate line in the circle. 
                     When the feature is shown by the circle of dots,
                     digitize it as an area.  Digitize a line  on the
                     circle  of  dots  to  form  an  outline.   The
                     feature may also be shown by a dashed line and
                     labeled "Pilings," in which case it is digitized
                     as a line.

          200 0466   Breakwater, jetty, pier, dock, causeway, or wharf
                     This code identifies features shown by symbols
                     156-158 (A); 112.69, 112.70, 112.96 (B); 512.43
                     through 512.45, 512.162 (C); or 2108.05, 2108.06
                     (D).  When the feature is shown by a line as in
                     symbols 156(A), 112.69(B), or 512.43(C), it is
                     digitized as a line.  When shown by symbols
                     112.70(B), or 512.46, 512.47 (C) also use this
                     code to indicate that it is a ruined structure
                     (see code 200 0618).  When shown by symbols
                     157(A) or 512.44(C), digitize it as an area.  Use
                     an arbitrary closure line (see code 200 0250) to
                     close the landward end of the symbol.  When shown
                     by symbols 158(A) or 512.45(C), also use this
                     code to indicate that the feature is covered (see
                     code 200 0608).  When shown by symbol 512.162(C),
                     also use this code to indicate that the feature
                     is submerged (see code 200 0617).

          200 0467   Exposed wreck or wreckage
                     This code identifies a feature shown by symbols
                     239, 240 (A); 512.139, 512.140 (C); or
                     2113.05(D).  When shown by symbol 239 digitize a
                     degenerate line on the center of the ship.  When
                     shown by symbol 240, digitize the feature as an
                     area.  Digitize the line of dots as the outline
                     of the area.

          200 0468   Sunken wreck
                     This code identifies a feature shown by symbols
                     241, 242 (A), or 512.141(C).  When shown by
                     symbol 242(A), digitize the feature by placing a
                     degenerate line on the center of the symbol. 
                     When the masts are exposed on a sunken wreck as
                     shown by symbols 241(A) or 512.141(C), digitize
                     the feature as an area.  Place the area point on
                     the center of
                     the symbol.  Digitize a line on the circle of
                     dots for the outline of the area.

          200 0469   Drydock
                     This code identifies a feature shown by symbols
                     162(A), 112.68(B), and 512.49(C).  These symbols
                     are in two pieces, the manmade shoreline
                     enclosing the water area and the tick-marked gate
                     that is placed in the opening of the drydock. 
                     The shoreline is digitized as a line identified
                     by the coincident feature code 209 0005.  Place
                     a degenerate line on the point of the V-shaped
                     tick mark.  Use this code on both parts of the
                     feature.

  3.11.7  Descriptive Attribute Codes
          Descriptive attribute codes are used to add to or qualify
          the meaning of another attribute code.  A descriptive
          attribute code is only used with another code: node, line,
          area, single-point, or general purpose.  The use of a
          descriptive attribute code is, in many cases, called for
          by the equivalent label on the source.  For example, a map
          may show  "sand pits," "gravel pits," "clay pits," or
          borrow pits."  In each case the identifying code for pits
          (200 0432) must be used with the code to describe the type
          of pit added; gravel (200 0609), sand (200 0610), clay
          (200 0611), or borrow (200 0612).

          200 0601   Underground
                     This code describes a feature that is labeled
                     "underground."  Do not use it to describe a
                     feature that by definition is always underground,
                     such as a mine shaft.

          200 0602   Under construction
                     This code describes any feature that is labeled
                     "under construction."

          200 0603   Abandoned
                     This code describes any feature labeled
                     "abandoned."

          200 0604   Water
                     This code describes a feature that is labeled
                     "water."

          200 0605   Oil
                     This code describes a feature that is labeled
                     "oil."

          200 0606   Gas
                     This code describes a feature that is labeled
                     "gas."

          200 0607   Chemical
                     This code describes a feature that is labeled
                     "chemical."

          200 0608   Covered
                     This code describes a pier or wharf that is
                     covered and is  shown by symbol 158(A).  It is
                     used with code 200 0466.

          200 0609   Gravel
                     This code describes a pit labeled "gravel."  It
                     is used with code 200 0432.

          200 0610   Sand
                     This code describes a pit labeled "sand."  It is
                     used with code 200 0432.

          200 0611   Clay
                     This code describes a pit labeled "clay."  It is
                     used with code 200 0432.

          200 0612   Borrow
                     This code describes a pit labeled "borrow."  It
                     is used with code 200 0432.

          200 0613   Radio
                     This code describes a tower labeled "radio."  It
                     is used with code 200 0305.

          200 0614   Lookout
                     This code describes a tower labeled "lookout." 
                     It is used with code 200 0305.

          200 0615   Unincorporated
                     This code describes a locality labeled
                     "unincorporated."  It is used with code 200 0410.

          200 0616   No population
                     This code describes a locality labeled
                     "unpopulated" or "no population."  It is used
                     with code 200 0410.

          200 0617   Submerged
                     This code describes any feature labeled
                     "submerged" such as a sewer line (200 0209).  Do
                     not use this code on a feature that by definition
                     is underwater, such as a sunken wreck.

          200 0618   Ruin
                     This code describes a feature that has the word
                     added to its label, such as the pier or wharf
                     ruin shown by symbol 112.70(B).  Do not use this
                     code on ruins described in instructions for code
                     200 0452.  This code is intended for features
                     that are not of the archeological type but are in
                     such a state of decay that they are no longer
                     used for their original purpose.

          200 0619   Caliche
                     This code describes a pit labeled "caliche."  It
                     is used with code 200 0432.

          200 0620   Chert
                     This code describes a pit labeled "chert."  It is
                     used with code 200 0432.

          200 0621   Cinder
                     This code describes a pit labeled "cinder."  It
                     is used with code 200 0432.

          200 0622   Pumice
                     This code describes a pit labeled "pumice."  It
                     is used with code 200 0432.

          200 0623   Shale
                     This code describes a pit labeled "shale."  It is
                     used with code 200 0432.

          200 0624   Scoria
                     This code describes a pit labeled "scoria."  It
                     is used with code 200 0432.


  3.11.8  Parameter Attribute Codes
          200 0000   Photorevised feature
                     This code is described in section 3.3.3.

          202 0---   Width in mils of feature to scale
                     Enter the width in mils, of a linear feature that
                     is shown to scale, in the spaces flush right.

          208 0000   Best estimate of position or classification
                     This code is described in section 3.3.3.

          209 00--   Coincident feature
                     This code is described in section 3.3.3.