U.S. Department of Commerce Bureau of the Census Geography Division, 2001, Census: TIGER/Line Files Version (MMYY) represents the month and year file created, U.S. Department of Commerce Bureau of the Census Geography Division, Washington, DC.Online Links:
- \\wvs1\Clients\Accomack\Current\Data\AccomackGIS_old.gdb
The map projection used is Lambert Conformal Conic.
Planar coordinates are encoded using coordinate pair
Abscissae (x-coordinates) are specified to the nearest 0.000128
Ordinates (y-coordinates) are specified to the nearest 0.000128
Planar coordinates are specified in survey feet
The horizontal datum used is North American Datum of 1983.
The ellipsoid used is Geodetic Reference System 80.
The semi-major axis of the ellipsoid used is 6378137.000000.
The flattening of the ellipsoid used is 1/298.257222.
Sequential unique whole numbers that are automatically generated.
Coordinates defining the features.
Positive real numbers that are automatically generated.
Positive real numbers that are automatically generated.
In order for others to use the information in the Census TIGER data base in a geographic information system (GIS) or for other geographic applications, the Census Bureau releases to the public extracts of the data base in the form of TIGER/Line files. Various versions of the TIGER/Line files have been released; previous versions include the 1990 Census TIGER/Line files, the 1992 TIGER/Line files, the 1994 TIGER/Line files, the 1995 TIGER/Line files, the 1997 TIGER/Line files, the 1998 TIGER/Line files, and the 1999 TIGER/Line files. The Redistricting Census 2000 TIGER/Line files were originally produced to support the Census 2000 Redistricting Data Program.
U.S. Department of Commerce Bureau of the Census Geography Division, Unpublished material, Census TIGER data base.
Data sources used in this process:
Data sources used in this process:
Accurate against Federal information Processing Standards (FIPS), FIPS Publication 6-4, and FIPS-55 at the 100% level for the codes and base names. The remaining attribute information has been examined but has not been fully tested for accuracy.
The information present in these files is provided for the purposes of statistical analysis and census operations only. Coordinates in the TIGER/Line files have six implied decimal places, but the positional accuracy of these coordinates is not as great as the six decimal places suggest. The positional accuracy varies with the source materials used, but generally the information is no better than the established national map Accuracy standards for 1:100,000-scale maps from the U.S. Geological Survey (USGS); thus it is NOT suitable for high-precision measurement applications such as engineering problems, property transfers, or other uses that might require highly accurate measurements of the earth's surface. The USGS 1:100,000-scale maps met national map accuracy standards and use coordinates defined by the North American Datum, 1983. For the contiguous 48 States, the cartographic fidelity of most of the Redistricting Census 2000 TIGER/Line files, in areas outside the 1980 census Geographic Base File/Dual Independent map Encoding (GBF/DIME) file coverage and selected other large metropolitan areas, compare favorable with the USGS 1:100,000-scale maps. The Census Bureau cannot specify the accuracy of features inside of what was the 1980 GBF/DIME-File coverage or selected metropolitan areas. The Census Bureau added updates to the TIGER/Line files that enumerators annotated on maps sheets prepared from the Census TIGER data base as they attempted to traverse every street feature shown on the Census 2000 map sheets; the Census Bureau also made other corrections from updated map sheets supplied by local participants for Census Bureau programs. The locational accuracy of these updates is of unknown quality. In addition to the Federal, State, and local sources, portions of the files may contain information obtained in part from maps and other materials prepared by private companies. Despite the fact the TIGER/Line data positional accuracy is not as high as the coordinate values imply, the six-decimal place precision is useful when producing maps. The precision allows features that are next to each other on the ground to be placed in the correct position, on the map, relative to each other, without overlap.
Data completeness of the TIGER/Line files reflects the contents of the Census TIGER data base at the time the TIGER/Line files (Redistricting Census 2000 version) were created.
The feature network of lines (as represented by Record Types 1 and 2) is compete for census purposes. Spatial objects in TIGER/Line belong to the "Geometry and Topology" (GT) class of objects in the "Spatial Data Transfer Standard" (SDTS) FIPS Publication 173 and are topologically valid. Node/geometry and topology (GT)-polygon/chain relationships are collected or generated to satisfy topological edit requirements. These requirements include: * Complete chains must begin and end at nodes. * Complete chains must connect to each other at nodes. * Complete chains do not extend through nodes. * Left and right GT-polygons are defined for each complete chain element and are consistent throughout the extract process. * the chains representing the limits of the files are free of gaps. The Census Bureau performed automated tests to ensure logical consistency and limits of files. All polygons are tested for closure. The Census Bureau uses its internally developed Geographic Update System to enhance and modify spatial and attribute data in the Census TIGER data base. Standard geographic codes, such as FIPS codes for states, counties, municipalities, and places, are used when encoding spatial entities. The Census Bureau performed spatial data tests for logical consistency of the codes during the compilation of the original Census TIGER data base files. Most of the Codes themselves were provided to the Census Bureau by the USGS, the agency responsible for maintaining FIPS 55. Feature attribute information has been examined but has not been fully tested for consistency.
Are there legal restrictions on access or use of the data?
- Access_Constraints: None
- Use_Constraints:
- None. Acknowledgment of the U.S. Bureau of the Census would be appreciated for products derived from these files. TIGER, TIGER/Line, and Census TIGER are registered trademarks of the Bureau of the Census.
(301) 457-1128 (voice)
(301) 457-4710 (FAX)
Redistricting Census 2000 TIGER/Line Files
No warranty, expressed or implied is made and no liability is assumed by the U.S. Government in general or the U.S. Census Bureau in specific as to the positional or attribute accuracy of the data. The act of distribution shall not constitute any such warranty and no responsibility is assumed by the U.S. Government in the use of these files.
| Data format: | TGRLN (compressed) (version Redistricting Census 2000) |
|---|---|
| Network links: |
www.census.gov/geo/www/tiger |
The online copy of the TIGER/Line files may be accessed without charge. See <http://www.census.gov/geo/www/tiger> for information on availability on CD-ROM/DVD and associated costs for these products.
To obtain more information about ordering TIGER/Line files visit <http://www.census.gov/geo/www/tiger>. Technical_Prequisites: The Redistricting Census 2000 TIGER/Line files contain geographic data only and do not include display or mapping software or statistical data. A list of vendors who have developed software capable of processing TIGER/Line files can be found by visiting <http://www.census.gov/geo/www/tiger>
(301) 457-1128 (voice)
tiger@census.gov