U.S. Department of Commerce, U.S. Census Bureau, Geography Divisi, 2005, SDETrims.DBO.Bound_110Congressional: TIGER/Line Files Each file contains a version code that uniquely identifies each specific release of a version of the TIGER/Line files. The version code (MMYY) represents the month and year that the data in the file was extracted from the TIGER database..Online Links:
- Service=sde:sqlserver:CHUCKNORRIS; Database=SDETrims; Version=dbo.DEFAULT
Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.000000. Longitudes are given to the nearest 0.000000. Latitude and longitude values are specified in Decimal degrees.
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.
(301) 763-1128 (voice)
(301) 457-4710 (FAX)
tiger@census.gov
In order for others to use the information in the Census TIGER database in a geographic information system (GIS) or for other geographic applications, the Census Bureau releases to the public extracts of the database in the form of TIGER/Line files.
U.S. Department of Commerce, U.S. Census Bureau, Geography Divisi, Unpublished material, Census TIGER database.
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 Census Bureau uses Global Positioning System (GPS) coordinates at road centerline intersections to evaluate the horizontal spatial accuracy of source files that may be used to realign road features in the TIGER database and test the horizontal spatial accuracy of the road features in the TIGER/Line files. The test compares a survey-grade GPS coordinate to its associated road centerline intersection in the TIGER file. The test is based upon an independent collection of GPS coordinates for a random sample of road intersections from a centerline file that meet certain criteria. The points are referred to as the sample points and are gathered through a private contractor working for the Census Bureau. Since the collection method uses survey-quality GPS-based field techniques, the resulting control points are considered "ground truth" against which the TIGER road centerline intersection coordinates are compared. The distances between the coordinates are calculated and the Census Bureau determines the Circular Error 95% (CE95). That is, the accuracy of the file in meters with 95% confidence. The CE95 can be calculated from the mean and standard deviation by using the formula: mean of differences plus (2.65 times the standard deviation). CE95 results reported for each file tested are determined using a spreadsheet with embedded statistical formula. The use and applicability of the spreadsheet and its embedded formula have been verified by Census Bureau statisticians. The basis of the calculation is the use of the root mean square error (RSME). This is the method as stated in the U.S. Government's Federal Geographic Data Committee Standard FGDC-STD-007.3-1998, Geospatial Positioning Accuracy Standards. Part 3: National Standard for Spatial Data Accuracy. The results of using this measure of accuracy are in compliance with Federal Spatial Data requirements. In terms of the Census Bureau application, the dataset coordinate values are those taken from the centerline file and the coordinate values from an independent source of higher accuracy are those acquired through the Census Bureau's contractor. Please note that the horizontal spatial accuracy, where reported, refers only to the realigned road features identified as matched to the positionally accurate source file with that accuracy. It is not the spatial accuracy of the TIGER/Line file as a whole.
Data completeness of the TIGER/Line files reflects the contents of the Census TIGER database at the time the TIGER/Line files (2005 Second Edition version) were created.
The feature network of lines (as represented by Record Types 1 and 2) is complete 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: (1) Complete chains must begin and end at nodes. (2) Complete chains must connect to each other at nodes. (3) Complete chains do not extend through nodes. (4) Left and right GT-polygons are defined for each complete chain element and are consistent throughout the extract process. (5) 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 database. Standard geographic codes, such as FIPS codes for states, counties, municipalities, county subdivisions, places, American Indian/Alaska Native/Native Hawaiian areas, and congressional districts 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 database files. Most of the codes for all geographic entities except states, counties, and congressional districts 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:
- Acknowledgment of the U.S. Census Bureau would be appreciated for products derived from these files. TIGER, TIGER/Line, and Census TIGER are registered trademarks of the U.S. Census Bureau. ZCTA is a trademark of the U.S. Census Bureau. The boundary information in the TIGER/Line files are for statistical data collection and tabulation purposes only; their depiction and designation for statistical purposes does not constitute a determination of jurisdictional authority or rights of ownership or entitlement and are they are not legal land descriptions. The horizontal spatial accuracy information present in these files is provided for the purposes of statistical analysis and census operations only. No warranty, expressed or implied is made with regard to the accuracy of the spatial accuracy, and no liability is assumed by the U.S. Government in general or the U.S. Census Bureau, specifically as to the spatial or attribute accuracy of the data. The TIGER/Line files may not be 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. 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.
(301) 763-1128 (voice)
(301) 457-4710 (FAX)
tiger@census.gov
2005 First Edition TIGER/Line Files
No warranty, expressed or implied is made with regard to the accuracy of these data, and no liability is assumed by the U.S. Government in general or the U.S. Census Bureau in specific as to the spatial 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. The boundary information in the TIGER/Line files are for statistical data collection and tabulation purposes only; their depiction and designation for statistical purposes does not constitute a determination of jurisdictional authority or rights of ownership or entitlement and they are not legal land descriptions.
| Data format: | TGRLN (compressed) |
|---|---|
| Network links: |
<http://www.census.gov/geo/www/tiger> |
| Media you can order: |
CD-ROM, DVD-ROM
(format ISO 9660)
|
The online copy of the TIGER/Line files may be accessed without charge. See https://censuscatalog.mso.census.gov/esales/start.swe?SWECmd=Start for information on availability on CD-ROM/DVD and associated costs for these products.
To obtain more information about ordering TIGER/Line files visit https://censuscatalog.mso.census.gov/esales/start.swe?SWECmd=Start
The TIGER/Line files contain geographic data only and do not include display or mapping software or statistical data. For information on how to use the TIGER/Line data with a specific software package users should contact the company that produced the software. A list of some vendors who have developed software capable of processing TIGER/Line files can be found by visiting <http://www.census.gov/geo/www/tiger>. The TIGER/Line files are provided in ASCII text format only. Users are responsible for converting or translating the files into a format used by their specific software package.
(301) 763-1128 (voice)
tiger@census.gov