TIGER/Line files are created by the U.S. Census Bureau and cover the entire United States. They are often referred to simply as TIGER files. For more information, see http://www.census.gov/geo/www/tiger/.
File listing
TIGER/Line files are text files and directory-based data sources. For example, one county folder TGR06059 contains several associated files:
TGR06059.RT1 TGR06059.RT2 TGR06059.RT4 TGR06059.RT5
TGR06059.RT6 TGR06059.RT7 TGR06059.RT8 TGR06059.RTA
TGR06059.RTC TGR06059.RTH TGR06059.RTI TGR06059.RTP
TGR06059.RTR TGR06059.RTS TGR06059.RTT TGR06059.RTZ
Data access/connection method
TIGER/Line access occurs through OGR. The full path to the directory containing the associated files is required in the CONNECTION string. The layer number is added to the CONNECTION string, after the path, separated by a comma: for example., CONNECTION "/tiger/data,0". The layer number in the map file is actually the ogrinfo layer number, minus one.
ogrinfo examples
Here's an example that uses ogrinfo on a TIGER directory to retrieve layer numbers:
> ogrinfo TGR06059 (NOTE that this is a directory)
ERROR 4: Tiger Driver doesn't support update.
Had to open data source read-only.
INFO: Open of 'TGR06059'
using driver 'TIGER' successful.
1: CompleteChain (Line String)
2: AltName (None)
3: FeatureIds (None)
4: ZipCodes (None)
5: Landmarks (Point)
6: AreaLandmarks (None)
7: Polygon (None)
8: PolygonCorrections (None)
9: EntityNames (Point)
10: PolygonEconomic (None)
11: IDHistory (None)
12: PolyChainLink (None)
13: PIP (Point)
14: TLIDRange (None)
15: ZeroCellID (None)
16: OverUnder (None)
17: ZipPlus4 (None)
For the CompleteChain Line layer, the ogrinfo layer number is 1. However, when referring to this layer in a map file CONNECTION, the layer number will be one less, 0.
Here's an example that uses ogrinfo to examine the structure of the TIGER layer CompleteChain:
> ogrinfo TGR06059 CompleteChain
ERROR 4: Tiger Driver doesn't support update.
Had to open data source read-only.
INFO: Open of 'TGR06059'
using driver 'TIGER' successful.
Layer name: CompleteChain
Geometry: Line String
Feature Count: 123700
Extent: (-118.125898, 33.333992) - (-117.412987, 33.947512)
Layer SRS WKT:
GEOGCS["NAD83",
DATUM["North_American_Datum_1983",
SPHEROID["GRS 1980",6378137,298.257222101]],
PRIMEM["Greenwich",0],
UNIT["degree",0.0174532925199433]]
MODULE: String (8.0)
TLID: Integer (10.0)
SIDE1: Integer (1.0)
SOURCE: String (1.0)
FEDIRP: String (2.0)
FENAME: String (30.0)
FETYPE: String (4.0)
FEDIRS: String (2.0)
CFCC: String (3.0)
FRADDL: String (11.0)
TOADDL: String (11.0)
FRADDR: String (11.0)
TOADDR: String (11.0)
FRIADDL: String (1.0)
TOIADDL: String (1.0)
FRIADDR: String (1.0)
TOIADDR: String (1.0)
ZIPL: Integer (5.0)
Map file example
LAYER
NAME Complete_Chain
TYPE LINE
STATUS DEFAULT
CONNECTIONTYPE OGR
CONNECTION "/path/to/data/tiger/TGR06059,0"
CLASS
COLOR 153 102 0
END
END # Layer
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