 APPENDIX A.--Standard DLG Distribution Format (Record Contents)--continued

 [Integer fields with a value of zero will have leading zeros suppressed.
For example, an I6 field would be "bbbbb0". (b = blank)][Any field with the format of D24.l5
which has a value of zero will be
          represented as "bbb0.0bbbbbbbbbbbbbbbbbb".  (b=blank)]

APPENDIX A.--Standard DLG Distribution Format (Record Contents)--continued


APPENDIX A.--Standard DLG Distribution Format (Record Contents)--continued

APPENDIX A.--Standard DLG Distribution Format (Record Contents)--continued


             APPENDIX A.--Standard DLG Distribution Format (Record Contents)--continued

             APPENDIX A.--Standard DLG Distribution Format (Record Contents)--continued


             APPENDIX A.--Standard DLG Distribution Format (Record Contents)--continued

             APPENDIX A.--Standard DLG Distribution Format (Record Contents)--continued

             APPENDIX A.--Standard DLG Distribution Format (Record Contents)--continued
             APPENDIX A.--Standard DLG Distribution Format (Record Contents)--continued

             APPENDIX A.--Standard DLG Distribution Format (Record Contents)--continued

             APPENDIX B.--Optional DLG Distribution Format (Record Contents)--continued

             APPENDIX B.--Optional DLG Distribution Format (Record Contents)--continued

             APPENDIX B.--Optional DLG Distribution Format (Record Contents)--continued

             APPENDIX B.--Optional DLG Distribution Format (Record Contents)--continued

             APPENDIX B.--Optional DLG Distribution Format (Record Contents)--continued

             APPENDIX B.--Optional DLG Distribution Format (Record Contents)--continued

             APPENDIX B.--Optional DLG Distribution Format (Record Contents)--continued

             APPENDIX B.--Optional DLG Distribution Format (Record Contents)--continued

             APPENDIX B.--Optional DLG Distribution Format (Record Contents)--continued

             APPENDIX B.--Optional DLG Distribution Format (Record Contents)--continued

             APPENDIX B.--Optional DLG Distribution Format (Record Contents)--continued

                             APPENDIX D.--DLG Attribute Codes--continued

                             APPENDIX D.--DLG Attribute Codes--continued

                             APPENDIX D.--DLG Attribute Codes--continued

                             APPENDIX D.--DLG Attribute Codes--continued

                             APPENDIX D.--DLG Attribute Codes--continued

                             APPENDIX D.--DLG Attribute Codes--continued

                             APPENDIX D.--DLG Attribute Codes--continued

                             APPENDIX D.--DLG Attribute Codes--continued

                             APPENDIX D.--DLG Attribute Codes--continued

                             APPENDIX D.--DLG Attribute Codes--continued


                                                                                                                            
                                              Logical Record Type A
                                                                                                                            
Record      Data                                Type                       Starting  Ending
Number      Element     Contents          (Fortran Notation)  Format        Byte      Byte            Comment               

A.l           1       Name of digital           ALPHA          A40           l          40      The name of the map will be
                      cartographic unit                                                         used when practical.

---         ---       Filler                     ---           ---           4l         4l      l space

A.l           2       Date of original          ALPHA          Al0           42         5l      Year of original source
                      source materials                                                          material, followed by latest
                                                                                                photorevision date if
                                                                                                applicable, for example,
                                                                                                l956, l965.                 

---         ---       Filler                     ---           ---           52         52      l space

A.l           3       Scale of original         INTEGER*4      I8            53         60      Scale denominator of source
                      source material                                                           material, for example,
                                                                                                100000.                     

---         ---       Filler                     ---           ---           6l         132     84 spaces                   

A.1          4-6      Coded Flags               ALPHA          A1            133        135     3 flags for future use

A.1           7       Coded Flag                ALPHA          A1            136        136     Database coded edge flag 

A.1           8       EDGEWS                    ALPHA          A1            137        137     Status flag for west edge,
                                                                                                values are:  b = unchecked
                                                                                                0 = passed, 1 = source un-
                                                                                                alignment, 2 = attribute dis-
                                                                                                continuity, 3 = attribute and
                                                                                                alignment discontinuity.


                                                                                                                            
                                        Logical Record Type A--continued
                                                                                                                            
Record      Data                                Type                       Starting  Ending
Number      Element     Contents          (Fortran Notation)  Format        Byte      Byte            Comment               

A.1           9       EDGEWR                    ALPHA          A1            138        138     Reason for EDGEWS, values
                                                                                                are:  b = unchecked, 4 =
                                                                                                Adjacent data unavailable,
                                                                                                5 = adjacent data does not
                                                                                                exist, 6 = temporal
                                                                                                discontinuity.

A.1          10       EDGENS                    ALPHA          A1            139        139     Status flag for north edge, 
                                                                                                values = b,0,1,2, or 3 as
                                                                                                above.

A.1          11       EDGENR                    ALPHA          A1            140       140      Reason for EDGENS, values
                                                                                                are b,4,5, or 6 as above.

A.1          12       EDGEES                    ALPHA          A1            141       141      Status flag for east edge
                                                                                                Values are b,0,1,2, or 3
                                                                                                as above.

A.1          13       EDGEER                    ALPHA          A1            142       142      Reason for EDGEES. Values
                                                                                                are b,4,5, or 6 as above.

A.1         14        EDGESS                    ALPHA          A1            143       143      Status flag for south edge.
                                                                                                Values are b,0,1,2, or 3
                                                                                                as above.

A.1         15        EDGESR                    ALPHA          A1            144       144      Reason for EDGEST.  Values
                                                                                                are b,4,5, or 6 as above.

A.2           1       DLG level code            INTEGER*2      I6            l          6       Code=3, DLG-3


                                                                                                                            
                                        Logical Record Type A--continued
                                                                                                                            
Record      Data                                Type                       Starting  Ending
Number      Element     Contents          (Fortran Notation)  Format        Byte      Byte            Comment               

A.2           2       Code defining             INTEGER*2      I6            7          l2      Code=l, Universal Transverse
                      ground planimetric                                                        Mercator (UTM)
                      reference system

A.2           3       Code defining zone        INTEGER*2      I6            l3         l8      Codes for UTM coordinate
                      in ground plan-                                                           zones are given in
                      imetric reference                                                         Appendix C.
                      system

A.2           4       Map projection            REAL*8         5D24.l5       l9         l38     This field contains the
                      parameters                                                                first 5 of l5 map projection
                                                                                                parameters.  Parameters
                                                                                                for the UTM projection are 
                                                                                                given in Appendix C.

---         ---       Filler                     ---           ---           l39        l44     6 spaces

A.3           1       Map projection            REAL*8         6D24.l5       l          l44     This record contains 
                      parameters                                                                projection parameters 6
                                                                                                thru ll.  Parameters for the
                                                                                                UTM projection are given
                                                                                                in Appendix C.

A.4           1       Map projection            REAL*8         4D24.l5       l           96     This field contains the
                      parameters                                                                last 4 projection
                                                                                                parameters.  Parameters for
                                                                                                the UTM projection are given
                                                                                                in Appendix C.

A.4           2       Code defining units of    INTEGER*2     I6             97         l02     Code=2, meters
                      measure for ground                                                             
                      planimetric coordinates                                                    
                      throughout the file                                                        
                                                                                                 


                                                                                                                            
                                        Logical Record Type A--continued
                                                                                                                            
Record      Data                                Type                       Starting  Ending
Number      Element     Contents          (Fortran Notation)  Format        Byte      Byte            Comment               

A.4           3       Resolution                REAL*8         D24.l5        l03        l26     The true ground distance
                                                                                                corresponding to one unit
                                                                                                (0.001 inch at map scale) in
                                                                                                the file internal reference
                                                                                                system.  For 1:100,000-scale
                                                                                                0.001 inch equals 2.54 
                                                                                                meters.

A.4           4       Accuracy code of          INTEGER*2     I6             l27        l32     Code=0, unknown accuracy
                      planimetric data                                                               

A.4           5       Number (n) of sides       INTEGER*2      I6            l33        l38     n=4
                      in the polygon which
                      defines the coverage
                      of the cell

---         ---       Filler                     ---           ---           139        l44     6 spaces   

A.5           1       A (4,2) array contain-    REAL*8         3(2D24.l5)    1          l44     The four-sided polygon will
A.6                   ing geographic                           2D24.l5       l          48      usually coincide with an
                      coordinates of the                                                        area defined by one of the
                      polygon which                                                             standard map formats of
                      contains the domain                                                       the National Mapping
                      of the DLG file                                                           Program.  Coordinates
                                                                                                are in geographic
                                                                                                longitude and latitude
                                                                                                in units of degrees and
                                                                                                decimal degrees and are
                                                                                                espressed in the order=SW,
                                                                                                NW, NE, SE.

---         ---       Filler                     ---           ---           49         l44     96 spaces
                                                                                                                             

                                                                                                                            
                                              Logical Record Type B
                                                                                                                            
Record      Data                                Type                       Starting  Ending
Number      Element     Contents          (Fortran Notation)  Format        Byte      Byte            Comment               

B.l           1       Parameters (Al, A2,       REAL*8         4D24.l5       1          96      X,Y coordinates resulting
                      A3, A4) of file-                                                          from this transformation
                      to-ground projection                                                      will be in ground meters in
                      transformation; the                                                       UTM zone defined by data
                      explicit form of the                                                      element 3 of record A.2.
                      transformation is:
                      X=Alx+A2y+A3
                      Y=Aly-A2x+A4
                      where:
                      x,y are coordinates in
                      file internal reference
                      system X,Y are coor-
                      dinates in map projec-
                      tion reference system    

B.l           2       Number (m) of regis-      INTEGER*2      I6            97         l02     m=4
                      tration points                                                            
                                                                                                

---         ---       Filler                     ---           ---           l03        l44     42 spaces 


                                                                                                                            
                                        Logical Record Type B--continued
                                                                                                                            
Record      Data                                Type                       Starting  Ending
Number      Element     Contents          (Fortran Notation)  Format        Byte      Byte            Comment               

B.2           1       A (4,3) array con-        ALPHA/         4(A2, 2I6)    l          56      The corners of a four-sided
                      taining identifications   INTEGER*2                                       polygon are used as
                      and coordinates of                                                        registration points.  The
                      registration points.                                                      identification sequence is
                      Coordinates are                                                           SW, NW, NE, SE.  The array
                      expressed in the file                                                     is stored by row.  
                      internal reference                                                        Coordinates in the file
                      system                                                                    internal reference system
                                                                                                are expressed in units of
                                                                                                thousandths of an inch and
                                                                                                fall in the range -32768 to
                                                                                                +32767.  These coordinates
                                                                                                correspond to the geographic
                                                                                                coordinates contained in 
                                                                                                records A.5 and A.6.

---         ---       Filler                     ---           ---           57         l44     88 spaces
                                                                                                                             

                                                                                                                            
                                              Logical Record Type C
                                                                                                                            
Record      Data                                Type                       Starting  Ending
Number      Element     Contents          (Fortran Notation)  Format        Byte      Byte            Comment               

C.l           1       Number (q) of             INTEGER*4      I6            1          6       1 q 32.  Up to 32 categories
                      categories                                                                can be represented in a
                      in the DLG file                                                           given file.  The value will
                                                                                                usually be between l and 5.

---         ---       Filler                     ---           ---           7          l44     l38 spaces  

C.21          1       A (q,7) array contain-    ALPHA/         q (A20,6I6)   1          56      This array is stored by 
to C.N                ing category names as     INTEGER*2                   (57        ll2)     row.  The first element is
                      well as maximum and                                                       the category name consisting
                      actual number of node,                                                    of 20 alphanumeric char
                      area, and line elements                                                   acters the first four of 
                      in each category                                                          which are unique.  Columns 2
                                                                                                and 3 of the array contain
                                                                                                maximum and actual number of 
                                                                                                nodes in the category.
                                                                                                Columns 4 and 5 contain
                                                                                                maximum and actual number of
                                                                                                areas in the category. 
                                                                                                Columns 6 and 7 are the
                                                                                                maximum and actual number
                                                                                                of line segments.  (Note:
                                                                                                the maximum number of any
                                                                                                element type within a
                                                                                                category is 4,770.  This
                                                                                                field is used only during
                                                                                                initial processing of data).

---         ---       Filler                     ---           ---           ---        ---     32 or 88 spaces
                                                                                                                            

1The number of categories "q" is given in record C.1.  There will be 56 bytes of data per category, and thus a maximum of
 two categories can be described on a 144-character record.  The space filler will vary in size depending on the value of
 "q."

                                                                                                                            
                                              Logical Record Type D
                                                                                                                            
Record      Data                                Type                       Starting  Ending
Number      Element     Contents          (Fortran Notation)  Format        Byte      Byte            Comment               

D.l           1       Type of element           ALPHA          A2            1          2       Code ='Nb' for Node element,
                      code                                                                            'Ab' for Area element.

D.l           2       Element's internal        INTEGER*2      I6            3          8       Unique within each category
                      identification number                                                     and element type.

D.l           3       x,y file coordinate       INTEGER*2      2I6           9          20      The representative area
                      of node point or repre-                                                   point is usually, but not
                      sentative point for the                                                   always, contained within the 
                      area element                                                              area it represents. 

D.l           4       Number (t) of class-      INTEGER*2      I6            2l         26      Absence of attribute codes
                      ification attributes                                                      is indicated by t=0.
                      which are attached to
                      the node or area element
                      (t 0)

D.l           5       Number (k) of pairs of    INTEGER*2      I6            27         32      k=0.  Not currently used.
                      text characters which are                                                                         
                      attached to the node or                                                                           
                      area element (k 0)

---         ---       Filler                     ---           ---           33         l44     ll2 spaces              

D.2           1       Code indicating a         ALPHA          A2            l          2       Code='Lb' for line segment
                      line segment graph
                      element                                                                                             

D.2           2       Line segment's internal   INTEGER*2      I6            3          8       This number is unique within
                      identification number                                                     each category and element
                                                                                                type.           

D.2           3       Internal identification   INTEGER*2      I6            9          l4      Number refers to data
                      number of starting node                                                   element 2 in record D.l.


                                                                                                                            
                                        Logical Record Type D--continued
                                                                                                                            
Record      Data                                Type                       Starting  Ending
Number      Element     Contents          (Fortran Notation)  Format        Byte      Byte            Comment               

D.2           4       Internal identification   INTEGER*2      I6            l5         20      Number refers to data
                      number of ending node                                                     element 2 in record D.l. 

D.2           5       Internal identification   INTEGER*2      I6            21         26      Number refers to data
                      number of left area                                                       element 2 in record D.l.

D.2           6       Internal identification   INTEGER*2      I6            27         32      Number refers to data
                      number of right area                                                      element 2 in record D.l. 

D.2           7       Number (v) of coordinate  INTEGER*2      I6            33         38      The value of v is between
                      pairs which define the                                                    2 and l500.
                      line segment

D.2           8       Number (t) of classifi-   INTEGER*2      I6            39         44      Absence of classification
                      cation attributes which                                                   attribute codes is indicated
                      are attached to the                                                       by t=0.
                      line segment (t 0)

D.2           9       Number (k) of pairs of    INTEGER*2      I6            45         50      k=0.  Not currently used.
                      text characters which                                                                             
                      are attached to the                                                                              
                      line segment (k 0)

                                                                                                                     
            ---       Filler                     ---           ---           5l         144     94 spaces
                                                                                                                       

                                                                                                                            
                                              Logical Record Type E
                                                                                                                            
Record      Data                                Type                       Starting  Ending
Number      Element     Contents          (Fortran Notation)  Format        Byte      Byte            Comment               

E.l to2     1         A (v,2) array contain-    INTEGER*2      v(2I6)        1                  Coordinates are expressed
E.n                   ing an ordered sequence                                                   in internal file reference
                      of coordinate pairs which                                                 system, in units of
                      define the image presen-                                                  thousandths of an inch.  
                      tation of a line element                                                  The array is stored by row.

---         ---       Filler                     ---           ---           ---        ---     0 to l32 spaces
                                                                                                                             

2The number of coordinate pairs, "v", is given in record D.2.  There will be v(2I6) coordinate pairs of which a maximum of
 l2 pairs will fit on a l44 character ASCII record.  The space filler will vary in size depending on the value of "v."  If
 "v" equals l2 or is an integer multiple of l2, there will be no spaces as filler at the end of the record.
                                                                                                                            
                                              Logical Record Type F
                                                                                                                            
Record      Data                                Type                       Starting  Ending
Number      Element     Contents          (Fortran Notation)  Format        Byte      Byte            Comment               

F.l3        1         A (t,2) array containing  INTEGER* 2     t(2I6)        1                  The array is stored by row
to F.n                major and minor classifi-                                                 with the first column con-
                      cation codes for a graph                                                  taining the major
                      element                                                                   classification attribute,
                                                                                                and the second column
                                                                                                containing the minor
                                                                                                classification attribute.

---         ---       Filler                     ---           ---           ---        ---     0 to l32 spaces
                                                                                                                             

3The number of feature (attribute) codes, "t" is given in the D.l and D.2 records.  The F record is an array of t(2I6)
 codes of which a maximum of l2(2I6) will fit on a l44 character ASCII record.  The space filler will vary depending on the
 value of "t".  If "t" is l2 or an integer multiple of l2 there will be no spaces as filler at the end of the record.

                                                                                                                            
                                   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      Descriptive text.        

2             1       Name of digital           ALPHA          A40           1          40      The name of the map followed
                      cartographic unit                                                         by the state two character 
                                                                                                designators.

---          ---      Filler                     ---           ---           41         41      l space                    

2             2       Date of original          ALPHA          Al0           42         51      Year of original source
                      source material                                                           material followed by latest
                                                                                                photorevision date if
                                                                                                applicable, for example,
                                                                                                l956, l965.
                                                                                                                        

---                   Filler                     ---           ---           52         52      l space                 

2             3       Scale of original         INTEGER*4      I8            53         60      Scale denominator of source
                      source material                                                           material, for example,
                                                                                                100000.

---                   Filler                     ---                         61         63      3 spaces

2                     Sectional indicator        ALPHA         ---           64         66      Codes S, or F for size  
                                                                                                of sector, plus sequence
                                                                                                number.

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

3                     Filler                    ---            ---           l          60      60 spaces

3            1-3      Coded Flags               ALPHA          A1            61         63      3 flags for future use

3             4       Coded Flag                ALPHA          A1            64         64      Database coded edge flag 

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

3             5       EDGEWS                    ALPHA          A1            65         65      Status flag for west edge,
                                                                                                values are:  b = unchecked
                                                                                                0 = passed, 1 = source un-
                                                                                                alignment, 2 = attribute dis-
                                                                                                continuity, 3 = attribute and
                                                                                                alignment discontinuity.

3             6       EDGEWR                    ALPHA          A1            66         66      Reason for EDGEWS, values
                                                                                                are:  b = unchecked, 4 =
                                                                                                Adjacent data unavailable,
                                                                                                5 = adjacent data does not
                                                                                                exist, 6 = temporal
                                                                                                discontinuity.

3             7       EDGENS                    ALPHA          A1            67         67      Status flag for north edge, 
                                                                                                values = b,0,1,2, or 3 as
                                                                                                above.

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

3             9       EDGEES                    ALPHA          A1            69        69       Status flag for east edge
                                                                                                Values are b,0,1,2, or 3
                                                                                                as above.

3             10      EDGEER                    ALPHA          A1            70        70       Reason for EDGEES. Values
                                                                                                are b,4,5, or 6 as above.

3             11      EDGESS                    ALPHA          A1            71        71       Status flag for south edge.
                                                                                                Values are b,0,1,2, or 3
                                                                                                as above.

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

3             12      EDGESR                    ALPHA          A1            72        72       Reason for EDGEST.  Values
                                                                                                are b,4,5, or 6 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      Code=l, UTM
                      planimetric reference
                      system                                                                                              

4             3       Code defining zone in     INTEGER*2      I6            13         18      Codes for UTM coordinate
                      ground planimetric                                                        zones are given in appendix
                      reference system                                                          C.                        

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

4             5       Resolution                REAL*4         Dl8.ll        25         42      The true ground distance
                                                                                                corresponding to one unit
                                                                                                (0.00l inch at map scale)
                                                                                                in the file internal coor-
                                                                                                dinate system used in data
                                                                                                collection.  For 1:100,000-
                                                                                                scale 0.001 inch equals 2.54
                                                                                                meters.

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

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

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

4             8       Number (n) of sides       INTEGER*2      I6            55         60      Usually 4.
                      in the polygon which
                      define the coverage of
                      the cell.  Number (n)                                                                             
                      also defines the number of
                      control-points

4             9       Number (q) of categories  INTEGER*2      I6            61         66      1 q 32.  Up to 32 cate-
                      in the DLG file                                                           gories can be represented
                                                                                                in a given file.  The value
                                                                                                will usually be between
                                                                                                l and 5.                

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

5-9           1       Projection parameters     REAL*8         3D24.l5       l          72      Three parameters on each of
                      for map transformation                                                    5 records.  Parameters for
                                                                                                the UTM projection are
                                                                                                given in Appendix C.  

10            1       Internal file-to-         REAL*4         4Dl8.ll       1          72      A transformation of this
                      map projection                                                            type is not required, since
                      transformation                                                            coordinates are expressed
                      parameters                                                                in a ground planimetric
                                                                                                coordinate system (usually
                                                                                                UTM).  These parameters are
                                                                                                however, valid for trans-
                                                                                                formation as described in
                                                                                                record B.1, data element 1,
                                                                                                of the standard format.    
                                                                                                                            

                                                                                                                            
                             FILE IDENTIFICATION AND DESCRIPTION RECORDS--continued
                                                                                                                            
Record      Data                                Type                       Starting   Ending
Number      Element     Contents          (Fortran Notation)  Format        Byte       Byte           Comment               


                                                                                                                            
                                      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          A2            1          2       "SW," "NW," "NE," or "SE"
                                                                                                for four quadrangle
                                                                                                corners.

                      Filler                                                 3          6       4 spaces

              2       Latitude                  REAL*4         Fl2.6         7          18      In degrees and decimal
                                                                                                degrees.

              3       Longitude                 REAL*4         Fl2.6         19         30      In degrees and decimal
                                                                                                degrees.

                      Filler                                                 31         36      6 spaces

              4       Internal file x           REAL*4         Fl2.2         37         48      In units in the appropriate
                                                                                                zone of the ground plani-
                                                                                                metric coordinate system.

              5       Internal file y           REAL*4       Fl2.2           49         60      In units in the appropriate
                                                                                                zone of the ground plani-
                                                                                                metric coordinate system.

---         ---       Filler                     ---          ---            61         72      l2 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.

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

              3       Number of nodes refer-    INTEGER*2      I6            25         30      Number of nodes referenced
                      enced in file                                                             in file as start and end
                                                                                                nodes of lines.

              4       Actual number of          INTEGER*2      I6            31         36      Only if some or all node
                      nodes in file                                                             records were excluded from
                                                                                                the file, would this number
                                                                                                be different from data
                                                                                                element 3.

                      Filler                     ---           ---           37         37      l space

              5       Presence of node-to-      INTEGER*2      Il            38         38      Flag=0, node-to-area
                      area linkage records                                                      linkage records not
                                                                                                present.1

              6       Presence of node-to-      INTEGER*2      Il            39         39      Flag=l, node-to-line
                      line linkage records                                                      linkage records are
                                                                                                included.1

            ---       Filler                     ---           ---           40         40      l zero or space

              7       Number of areas refer-    INTEGER*2      I6            41         46      Number of areas referenced
                      enced in file                                                             in file as areas left and
                                                                                                areas right of lines.
                                                                                                                             

1The flags for lists present or absent are the current default values, and are the only current values used.

                                                                                                                            
                                 DATA CATEGORY IDENTIFICATION RECORDS--continued
                                                                                                                            
Record      Data                                Type                       Starting   Ending
Number      Element     Contents          (Fortran Notation)  Format        Byte       Byte           Comment               

1-q           8       Actual number of areas    INTEGER*2      I6            47         52      Only if some or all area
                      in file                                                                   records were excluded from
                                                                                                the file would the number
                                                                                                be different from the data
                                                                                                element 7. 

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

              9       Presence of area-to-      INTEGER*2      Il            54         54      Flag=0, area-to-node
                      node linkage records                                                      linkage records not
                                                                                                present.1

             10       Presence of area-to-      INTEGER*2      Il            55         55      Flag=l, area-to-line
                      line linkage records                                                      linkage records are
                                                                                                included.1

             11       Presence of area-         INTEGER*2      Il            56         56      Flag=0, area-coordinate
                      coordinate lists                                                          lists not present.1

             12       Number of lines           INTEGER*2      I6            57         62      Number of lines referenced
                      referenced in file                                                        in area-to-line and node-
                                                                                                to-line records.

             13       Actual number of          INTEGER*2      I6            63         68      Only if some lines were
                      lines in file                                                             excluded from the file
                                                                                                would this number be
                                                                                                different from data element
                                                                                                12.

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

             14       Presence of line-         INTEGER*2      Il            72         72      Flag=l, line-coordinate
                      coordinate lists                                                          lists are included.1
                                                                                                                             

1The flags for lists present or absent are the current default values, and are the only current values used.

                                                                                                                            
                                      NODE AND AREA IDENTIFICATION RECORDS
                                                                                                                            
Record      Data                                Type                       Starting   Ending
Number      Element     Contents          (Fortran Notation)  Format        Byte       Byte           Comment               

              1       Record type               ALPHA          Al            1          1       "N" or "A"

              2       Element internal          INTEGER*2      I5            2          6       This value is unique within
                      ID number                                                                 each category and element
                                                                                                type.

              3       Coordinates of node       REAL*4         2Fl2.2        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      Blank or zero (0).  These 
                      an area list (for nodes),                                                 lists are not currently
                      or in a node list                                                         included.
                      (for areas) 

              5       Number of elements in     INTEGER*2      I6            37         42      Number of line segments 
                      line segment list                                                         that intersect at the node,
                                                                                                or bound the area.

              6       Number of x,y or          INTEGER*2      I6            43         48      Blank or zero (0).  These
                      lat-long points                                                           lists are not currently
                      in area-coordinate                                                        included.
                      list

              7       Number of attributes      INTEGER*2      I6            49         54      Number of attributes
                      listed                                                                    listed.

              8       Number of text            INTEGER*2      I6            55         60      Zero (0).  There are no 
                      characters listed                                                         text attributes for 7.5-
                                                                                                and 15-minute DLG data.

              9       Number of islands         INTEGER*2      I6            61         66      Area records only, 6 spaces
                      within area                                                               for node records.

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


NODE-TO-LINE LINKAGE RECORDS

FORTRAN FORMAT (l2I6), for each node:  The list consists of line segment internal ID numbers (which appear in bytes 2-6 of
the line identification records).  The line segments which begin at this node are included in the list as positive ID
numbers.  The line segments which terminate at this node are included as negative ID numbers.  There is no logical order to
the list.

AREA-TO-LINE LINKAGE RECORDS

FORTRAN format (l2l6), for each area:  The list consists of line segment internal ID numbers (which appear in bytes 2-6 of
the line identification records) and, for those areas with islands (indicated by bytes 6l-66 of the area's first record),
zero (0) elements marking the beginning of islands.  Line segments with this area to the right are included as positive ID
numbers.  Line segments 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).  A zero (0) element is inserted in the list before
each island sublist.

                                                                                                                            
                                           LINE IDENTIFICATION RECORDS
                                                                                                                            
Record      Data                                Type                       Starting   Ending
Number      Element     Contents          (Fortran Notation)  Format        Byte       Byte           Comment               

              l       Record type                              Al            l          l       "L"

              2       Element internal ID number               I5            2          6       This number is unique within
                                                                                                each category and element
                                                                                                type.

              3       Starting node                            I6            7          l2      Internal ID number.  This
                                                                                                refers to data element 2 of
                                                                                                the node identification
                                                                                                record.

              4       Ending node                              I6            l3         l8      Internal ID number.  This
                                                                                                refers to data element 2 of
                                                                                                the node identification
                                                                                                record.

              5       Left area                                I6            l9         24      Internal ID number.  This
                                                                                                refers to data element 2 of
                                                                                                the area identification
                                                                                                record.

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

            ---       Filler                                   ---           3l         42      l2 spaces

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

              8       Number of attributes listed              I6            49         54      Number of attributes (or two
                                                                                                element attribute pairs)
                                                                                                listed.

              9       Number of text characters listed         I6            55         60      Zero (0).  There are no text
                                                                                                data associated with 7.5-
                                                                                                and l5-minute DLG data.  
                                                                                                                         

COORDINATE STRING RECORDS

FORTRAN format (3(2Fl2.2)):  The coordinates are in appropriate units in the designated ground planimetric coordinate
system (usually meters in UTM).  The file-to-map projection parameters in Header record l0 are set to (l.0,0.0,0.0,0.0) for
real map projection coordinates (the transformation formulas still apply).

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.

                                                                                                                             
                                                                        MAJOR   MINOR             
DATA CATEGORY            TYPE OF CODE             APPLICATION           CODE    CODE          DESCRIPTION                    

Combined hydrography     Feature identification   Nodes                 050     000l   Upper origin of stream
                                                                                0002   Upper origin of stream at water body
                                                                                0003   Sink, channel no longer evident
                                                                                0004   Stream entering water body
                                                                                0005   Stream exiting water body

                                                  Areas                 000     0000   Area outside graph
                                                                        050     0l00   Alkali flat
                                                                                0l0l   Reservoir
                                                                                0l02   Covered reservoir
                                                                                0l03   Glacier or permanent snowfield
                                                                                0l04   Salt evaporator
                                                                                0l05   Inundation area
                                                                                0l06   Fish hatchery or farm
                                                                                0l07   Industrial water impoundment
                                                                                0l08   Area to be submerged
                                                                                0l09   Sewage disposal pond or
                                                                                        filtration beds
                                                                                0ll0   Tailings pond
                                                                                0lll   Marsh, wetland, swamp, bog
                                                                                0ll2   Mangrove area
                                                                                0ll3   Rice field
                                                                                0ll4   Cranberry bog
                                                                                0ll5   Flats (tidal, mud, sand, gravel)
                                                                                0ll6   Bays, estuaries, gulfs, oceans, seas
                                                                                0117   Shoal
                                                                                0118   Soda evaporator

                                                  Lines                         0200   Shoreline
                                                                                020l   Manmade shoreline
                                                                                0202   Closure line, (water-water)
                                                                                0203   Indefinite shoreline
                                                                                0204   Apparent limit
                                                                                0205   Outline of a Carolina bay
                                                                                0206   Danger curve

                                                                                                                             
                                                                        MAJOR   MINOR             
DATA CATEGORY            TYPE OF CODE             APPLICATION           CODE    CODE          DESCRIPTION                    

Combined hydrography     Feature identification   Points                050     0300   Spring
 (cont'd.)                                        (Degenerate Lines)            030l   Non-flowing well
                                                                                0302   Flowing well
                                                                                0303   Riser
                                                                                0304   Geyser
                                                                                0305   Windmill

                                                  Multiple Element              0400   Rapids
                                                       Types                    040l   Falls
                                                                                0402   Gravel pit or quarry filled with water
                                                                                0403   Gaging station
                                                                                0404   Pumping station
                                                                                0405   Water intake
                                                                                0406   Dam or weir
                                                                                0407   Canal lock or sluice gate
                                                                                0408   Spillway
                                                                                0409   Gate (flood, tidal, head, check)
                                                                                04l0   Rock
                                                                                04ll   Crevasse
                                                                                04l2   Stream
                                                                                04l3   Braided stream
                                                                                04l4   Ditch or canal
                                                                                04l5   Aqueduct
                                                                                04l6   Flume
                                                                                04l7   Penstock
                                                                                04l8   Siphon
                                                                                04l9   Channel in water area
                                                                                0420   Wash or ephemeral drain
                                                                                042l   Lake or pond
                                                                                0422   Coral reef
                                                                                0423   Sand in open water
                                                                                0424   Spoil area

                                                                                                                             
                                                                        MAJOR   MINOR             
DATA CATEGORY            TYPE OF CODE             APPLICATION           CODE    CODE          DESCRIPTION                    

Combined hydrography     Descriptive              Multiple Element      050     060l   Underground
 (cont'd.)                                             Types                    0602   Overpassing
                                                                                0603   Elevated
                                                                                0604   Tunnel
                                                                                0605   Right bank
                                                                                0606   Left bank
                                                                                0607   Under construction
                                                                                0608   Salt
                                                                                0609   Unsurveyed
                                                                                06l0   Intermittent
                                                                                06ll   Abandoned or discontinued
                                                                                06l2   Submerged or sunken
                                                                                06l4   Dry
                                                                                06l5   Mineral or hot (sulphur, alkali, etc.)
                                                                                06l6   Navigable, transportation
                                                                                06l7   Underpassing
                                                                                0618   Earthen construction

                                                                        050     0000   Photorevised feature

                         Parameter                Multiple Element      05N     ----   Water surface elevation
                                                        Types                           N=l for feet, 2 for meters, 6 for
                                                                                        feet below datum, and 7 for meters
                                                                                        below datum.  Elevation value in four
                                                                                        spaces, right justified.
                                                                        053     ----   Angle of clockwise rotation (nearest
                                                                                        whole degree)
                                                                        055     ----   River mile, value in four spaces,
                                                                                        right justified
                                                                        058     0000   Best estimate of classification
                                                                                        or position
                                                                        059     00--   Coincident feature (enter first two
                                                                                        digits of major code for category of
                                                                                        coincident feature in blanks, right
                                                                                        justified.
                                                                                                                             


                                                                                                                             
                                                                        MAJOR   MINOR             
DATA CATEGORY            TYPE OF CODE             APPLICATION           CODE    CODE          DESCRIPTION                    

Transportation, Roads    Feature identification   Nodes                 l70     000l   Bridge abutment
  and Trails                                                                    0002   Tunnel portal
                                                                                0004   Gate
                                                                                0005   Cul-de-sac
                                                                                0006   Dead end


                                                  Areas                 000     0000   Area outside graph

                                                  Lines                 l70     020l   Primary route, class 1, symbol
                                                                                        undivided
                                                                                0202   Primary route, class 1, symbol
                                                                                        divided by centerline
                                                                                0203   Primary route, class 1 divided,
                                                                                        lanes separated
                                                                                0204   Primary route, class 1, one way, other
                                                                                        than divided highway
                                                                                0205   Secondary route, class 2, symbol
                                                                                        undivided
                                                                                0206   Secondary route, class 2, symbol
                                                                                        divided by centerline
                                                                                0207   Secondary route, class 2, symbol
                                                                                        divided, lanes separated
                                                                                0208   Secondary route, class 2, one way,
                                                                                        other then divided highway
                                                                                0209   Road or street, class 3
                                                                                0210   Road or street class 4
                                                                                0211   Trail, class 5, other than four wheel
                                                                                        drive vehicle
                                                                                02l2   Trail, class 5, four wheel drive
                                                                                        vehicle
                                                                                0213   Footbridge
                                                                                02l4   Ferry crossing
                                                                                02l5   Perimeter of parking area

                                                                                                                             
                                                                        MAJOR   MINOR             
DATA CATEGORY            TYPE OF CODE             APPLICATION           CODE    CODE          DESCRIPTION                    

Transportation, Roads    Feature identification   Lines (cont'd.)       170     02l6   Arbitrary extension of line (join or
  and Trails (cont'd.)                                                                              closure)
                                                                                02l7   Road or street, class 3, symbol
                                                                                        divided by centerline
                                                                                0218   Road or street, class 3, divided
                                                                                        lanes separated

                                                  Points                        NONE
                                                  (Degenerate Lines)            

                                                  Multiple Element      l70     0401   Traffic circle
                                                       Types                    0402   Cloverleaf or interchange
                                                                                0403   Toll gate, toll plaza or perimeter of
                                                                                        toll plaza
                                                                                0404   Weigh station

                          Descriptive             Multiple Element      170     0600   Historical
                                                       Types                    0601   In tunnel
                                                                                0602   Overpassing, on bridge
                                                                                0603   Under construction, classification 
                                                                                        known
                                                                                0604   Under construction, classification 
                                                                                        unknown
                                                                                0605   Labeled "old railroad grade"
                                                                                0606   Submerged or in ford
                                                                                0607   Underpassing
                                                                                0608   Limited access
                                                                                0609   Toll road
                                                                                0610   Privately operated or controlled 
                                                                                        public access
                                                                                0611   Proposed
                                                                                0612   Double-decked

                                                                                                                             
                                                                        MAJOR   MINOR             
DATA CATEGORY            TYPE OF CODE             APPLICATION           CODE    CODE          DESCRIPTION                    

Transportation, Roads     Descriptive (cont'd)    Multiple Element      170     0613   In service facility or rest area
  and Trails (cont'd)                                  Types (cont'd)           0614   Elevated
                                                                                0615   Bypass route
                                                                                0616   Alternate route
                                                                                0617   Business route
                                                                                0618   On drawbridge
                                                                                0619   Spur
                                                                                0650   Road width 46-55 feet, 0.025 inches
                                                                                        at 1:24,000
                                                                                0651   Road width 56-65 feet, 0.030 inches
                                                                                        at 1:24,000
                                                                                0652   Road width 66-75 feet, 0.035 inches
                                                                                        at 1:24,000
                                                                                0653   Road width 76-85 feet, 0.040 inches
                                                                                        at 1:24,000
                                                                                0654   Road width 86-95 feet, 0.045 inches
                                                                                        at 1:24,000
                                                                                0655   Road width 96-105 feet, 0.050 inches
                                                                                        at 1:24,000
                                                                                0656   Road width 106-115 feet, 0.055 inches
                                                                                        at 1:24,000
                                                                                0657   Road width 116-125 feet, 0.060 inches
                                                                                        at 1:24,000
                                                                                0658   Road width 126-135 feet, 0.065 inches
                                                                                        at 1:24,000
                                                                                0659   Road width 136-145 feet, 0.070 inches 
                                                                                        at 1:24,000


                                                                                                                             
                                                                        MAJOR   MINOR             
DATA CATEGORY            TYPE OF CODE             APPLICATION           CODE    CODE          DESCRIPTION                    

Transportation, Roads     Parameter               Multiple Element      170     0000   Photorevised feature
  and Trails (cont't)                                  Types            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 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

                                                                                                                             

Transportation,           Feature identification  Nodes                 180     0001   Bridge abutment
  Railroads                                                                     0002   Tunnel portal

                                                  Areas                 000     0000   Area outside graph

                                                  Lines                 180     0201   Railroad
                                                                                0202   Railroad in street or road
                                                                                0204   Carline
                                                                                0205   Cog railroad, incline railway
                                                                                        logging tram
                                                                                0207   Ferry crossing

                                                                                                                             
                                                                        MAJOR   MINOR             
DATA CATEGORY            TYPE OF CODE             APPLICATION           CODE    CODE          DESCRIPTION                    

Transportation,          Feature identification   Lines (cont'd)        180     0208          Railroad siding
  Railroads (cont'd)                                                            0209          Perimeter or limit of yard
                                                                                0210          Arbitrary line extension (join,
                                                                                               closure)

                                                  Points                NONE
                                                  (Degenerate lines)

                                                  Multiple Element      180     0400           Railroad station, perimeter of
                                                       Types                                    station
                                                                                0401           Turntable
                                                                                0402           Roundhouse

                         Descriptive              Multiple Element      180     0600           Historical
                                                       Types                    0601           In tunnel
                                                                                0602           Overpassing, on bridge
                                                                                0603           Abandoned
                                                                                0604           Dismantled
                                                                                0605           Underpassing
                                                                                0606           Narrow gauge
                                                                                0607           In snowshed or under structure
                                                                                0608           Under construction
                                                                                0609           Elevated
                                                                                0610           Rapid transit
                                                                                0611           On drawbridge
                                                                                0612           Private
                                                                                0613           U.S. Government
                                                                                0614           Juxtaposition

                         Parameter                Multiple Element      180     0000          Photorevised feature
                                                       Types            181     ----          Number of tracks
                                                                        188     0000          Best estimate of position or
                                                                                               classification
                                                                        189     00--          Coincident feature
                                                                                                                             

                                                                                                                             
                                                                        MAJOR   MINOR             
DATA CATEGORY            TYPE OF CODE             APPLICATION           CODE    CODE          DESCRIPTION                    

Transportation,          Feature identification   Nodes                 190     0001          End of transmission line at
  pipelines, trans-                                                                            power station, substation, or
  mission lines,                                                                               hydroelectric plant
  miscelaneous trans-                                                           0002          End of pipeline at oil or gas
  portation features                                                                           field
                                                                                0003          End of pipeline at refinery, 
                                                                                               depot, or tank farm

                                                  Areas                 000     0000          Area outside the graph

                                                  Lines                 190     0201          Pipeline
                                                                                0202          Power transmission line
                                                                                0203          Telephone or telegraph line
                                                                                0204          Aerial tramway, monorail, ski
                                                                                               lift
                                                                                0205          Arbitrary extension closure 
                                                                                               line

                                                  Points                190     0300          Seaplane anchorage
                                                  (Degenerate lines)

                                                  Multiple Element      190     0400          Power station
                                                       Types                    0401          Substation
                                                                                0402          Hydroelectric Plant
                                                                                0403          Landing strip, airport, 
                                                                                               perimeter of airport
                                                                        190     0404          Heliport, perimeter of heliport
                                                                                0405          Launch complex, perimeter of 
                                                                                               launch complex
                                                                                0406          Pumping station, compressor 
                                                                                               station
                                                                                0407          Seaplane ramp or landing area


                                                                                                                             
                                                                        MAJOR   MINOR             
DATA CATEGORY            TYPE OF CODE             APPLICATION           CODE    CODE          DESCRIPTION                    

Transportation,          Descriptive               Multiple Element     190     0600          Underground
  pipelines, trans-                                     Types                   0601          Under construction
  mission lines,                                                                0602          Abandoned
  miscellaneous trans-                                                          0603          Above ground
  portation features                                                            0604          Labeled "closed"
  (cont'd)                                                                      0605          Unimproved, loose surface
                                                                                0606          Submerged
                                                                                0607          Nuclear

                         Parameters                Multiple Element     190     0000          Photorevised feature
                                                        Types           193     0000          Angle of clockwise rotation
                                                                                               (nearest whole degree)
                                                                        198     0000          Best estimate of position or
                                                                                               classification
                                                                        199     00--          Coincident feature
                                                                                                                             

