DATABASE NAME

     TRANSIT:  Fixed guideway transit systems in the United
     States

DATABASE DESCRIPTION

     A geographic and topological network database of fixed
     guideway transit systems in the United States, showing
     right-of-way alignments, junctions, termini, stations and
     many maintenance yards.  Transit systems include heavy rail,
     light rail, monorail, automated guideway, cable car, ferry
     boat, inclined plane and high-occupancy vehicle (HOV) lanes.

ORIGINATING AGENCY

     Volpe National Transportation Systems Center

AGENCY RESPONSIBLE FOR MAINTAINING DATA

     Federal Transit Administration

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 Bureau of Census 1992 TIGER files supplemented by
     editing performed by the Volpe National Transportation
     Systems Center

ACCURACY

     50 m (165 ft) root-mean square positional accuracy

TYPE OF GIS DATABASE

     Line database with nodes and links

FILES/SIZE/NUMBER OF RECORDS

     Two ASCII files for each transit system for each city:  112
     files total

     1)   node files contain node locations and attributes
     2)   link files contain link attributes and shapes for links

     File naming convention is as follows:
          node file:     xxx_yy.pnt
          link file:     xxx_yy.lin
     where xxx is the city abbreviation and yy is the code for
     type of transit system (see FILE STRUCTURE for transit type
     codes)

     Approximate size of all files:     657,000 bytes
     Approximate number of nodes:       undetermined
     Approximate number of links:       undetermined

FILE STRUCTURE

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

     The Node File

   FIELD  ITEM                TYPE      REMARKS

     1    Node ID             Num       Unique identification
                                        number
     2    Longitude           Float     Longitude of node in
                                        decimal degrees (explicit
                                        decimal)
     3    Latitude            Float     Latitude of node in
                                        decimal degrees (explicit
                                        decimal)
     4    Type                Char      Type of node
                                        1    Crossing
                                        2    Transit station
                                        3    Maintenance yard
                                        4    End of line
                                        5    Junction
                                        8    Change of attribute
     5    Name                Char      Name of node if
                                        applicable
     6    Control Section     Num       Not used
     7    Milepost            Float     Linear reference location
                                        of node, not used
     8    Routes Served       Char      Name(s) of route(s) on
                                        fixed guideway served by
                                        this node

The Link File

   FIELD  ITEM                TYPE REMARKS

     1    "From" node number  Num       Node ID in xxx_yy.pnt
     2    "To" node number    Num       Node ID in xxx_yy.pnt
     3    Link ID             Num       Unique identification
                                        number
     4    Length              Float     Explicit decimal given
     5    Direction           Num       Always 0
     6    Transit Type        Char      Type of transit system
                                        AG   Automated guideway
                                        CC   Cable car
                                        FB   Ferry boat
                                        HOV  High-occupancy
                                             vehicle lanes
                                        HR   Heavy rail
                                        IP   Inclined plane
                                        LR   Light rail
                                        MR   Monorail
     7    Routes Served       Char      Name(s) of route(s) on
                                        fixed guideway served by
                                        this link
     8    Number of Tracks    Num       Number of tracks on this
                                        link, not used
     9    Grade/Elevation     Char      Code defining grade of
                                        link
                                        1    At grade
                                        2    Elevated
                                        3    Below grade
     10   Status              Char      Current status of link
                                        1    Planned
                                        2    Out of service
                                        3    Active
     11   FIPS Code           Num       Urban FIPS code, not used
     12   Control Section     Num       Not populated
     13   CS Type             Char      Not populated
     14   Start MPA           Num       Not populated
     15   End MPA             Num       Not populated
     16   CS/Sequence         Num       Not populated
     17   Edit date           Char      Not populated
     18   Filler              Float     Future use
     19   Filler              Float     Future use
     20   Filler              Float     Future use
     21   Filler              Float     Future use
     22   N                   Num       Number of following
                                        longitude-latitude pairs
                                        in decimal degrees
     23   Longitude of "From" Float     Explicit decimal} First 
     24   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

     The fixed-guideway alignments were digitized by hand, using
     1992 TIGER files as the underlying base map, and original
     source material from the various U.S. transit systems to
     locate stations and other important features.  The source
     material varied, ranging from non-geographic system maps, to
     detailed engineering drawings.  Overall geographic accuracy is
     consistent with that of the 1992 TIGER files for each urban
     area.  Attribute data was appended, based on original source
     material from the transit systems.
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