DATABASE NAME

     MEXICO:  Mexican Boundaries

DATABASE DESCRIPTION

     Shorelines and international boundaries for Mexico and its
     states.

ORIGINATING AGENCY

     Volpe National Transportation Systems Center

AGENCY RESPONSIBLE FOR MAINTAINING DATA

     Bureau of Transportation Statistics

CONTACT

     National Transportation Atlas Databases
     Bureau of Transportation Statistics
     U.S. Department of Transportation
     Washington, DC  20590
     (202) 366-DATA
     Internet:  info@bts.gov

SOURCE

     1:1,000,000 Digital Chart of the World supplemented by
     editing performed by the Volpe National Transportation
     Systems Center

ACCURACY

     700 m (2,200 ft) root-mean square positional accuracy

TYPE OF GIS DATABASE

     Area database with polygons and links

FILES/SIZE/NUMBER OF RECORDS

     Two files

     1)   mex_bdry.ply   polygon file contains area attributes
     2)   mex_bdry.lin   link file contains shapes for links

     Approximate size of files:    420,000 bytes
     Approximate number of areas:  32
     Approximate number of links:  800

FILE STRUCTURE

     The files are ASCII-comma delimited.  Character fields are
     enclosed in quotation marks.

     The Polygon File

   FIELD  ITEM                TYPE      REMARKS

     1    ID                  Num       Unique Identification
                                        number
     2    Area                Float     Area of state (sq mi)
     3    Name                Char      Name of state
     4    Long1               Num       Future use
     5    Long2               Num       Future use
     6    Char1_Key           Char      Future use
     7    Char2               Char      Future use
     8    Real1               Float     Future use
     9    Real2               Float     Future use
     10   Real3               Float     Future use

The Link File

   FIELD  ITEM                TYPE      REMARKS

     1    Polyleft            Num       Polygon Id from
                                        mex_bdry.ply on left side
                                        of the link
     2    Polyright           Num       Polygon Id from
                                        mex_bdry.ply on right
                                        side of the link
     3    N                   Num       Number of following
                                        Longitude-Latitude pairs
                                        in decimal degrees
     4    Longitude 1st pair  Float     Explicit decimal}
     5    Latitude 1st pair   Float     Explicit decimal} 

          Long.-Lat. pairs    Float     Shape points of the link
          repeat N-2 times    Float     in pairs of long.-lat.

          Longitude last pair Float     Explicit decimal}
          Latitude last pair  Float     Explicit decimal}

DISCUSSION

     No additional discussion.

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