DATABASE NAME

     MSA: Metropolitan Statistical Areas

DATABASE DESCRIPTION

     Metropolitan Statistical Areas for the United States.

ORIGINATING AGENCY

     Oak Ridge National Laboratory

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

     1:100,000 Census TIGER/Line records supplemented by editing
     performed by Oak Ridge National Laboratory

ACCURACY

     80 m (260 ft) root-mean square positional accuracy

TYPE OF GIS DATABASE

     Area database with polygons and links

FILES/SIZE/NUMBER OF RECORDS

     Two ASCII files

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

     Approximate size of files:    392,000 bytes
     Approximate number of areas:  330
     Approximate number of links:  2600

FILE STRUCTURE

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

     The Polygon File

   FIELD  ITEM                TYPE      REMARKS
     1    Polygon ID          Num       Unique record number
     2    Area                Float     Area of MSA, sq mi
     3    Name                Char      Name of MSA
     4    State               Char      State Postal Code
     5    MSA Code            Num       MSA code, currently blank
     6    Filler              Num       Future use
     7    Filler              Num       Future use

     The Link File

   FIELD  ITEM                TYPE REMARKS

     1    Polyleft            Num       Polygon Id to the left
                                        side of the line
     2    Polyright           Num       Polygon Id to the right
                                        side of the line
     3    N                   Num       Number of following
                                        Longitude-Latitude pairs
                                        in decimal degrees
     4    Longitude of "From" Float     Explicit decimal} First 
     5    Latitude of "From"  Float     Explicit decimal} pair

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

          Longitude of "To"   Float     Explicit decimal}  Final
          Latitude of "To"    Float     Explicit decimal}  pair

DISCUSSION

     No additional discussion.