Topologically Integrated Geographic Encoding and Referencing

TIGER or topologically Integrated Geographic Encoding and Referencing is a data format that is used by the United States Census Bureau to describe land attributes such as roads, railway lines, buildings, rivers and lakes as well as in other areas such as the census. TIGER was developed to improve the census of the United States.

The TIGER files themselves do not contain demographic data but only the cartographic data. The TIGER data are available for free, as a work of the United States government is basically public domain.

Data Coverage

The TIGER data include the United States, Puerto Rico, the U.S. Virgin Islands, American Samoa, Guam, the Commonwealth of the Northern Mariana Islands and the Midway Islands.

TIGER includes both the land attributes such as roads, buildings, rivers and lakes as well as areas such as counties, survey areas for the census, etc. Some of the geographic areas included are political areas such as counties, congressional districts or school districts. Others are statistical areas such as collection areas for the census or approximate postcode areas ( not to be confused with the real zip code areas). This approximate areas are used as change 3% of the zip codes regularly. They can therefore not be used for a long time for statistical purposes.

Data formats

The last TIGER data, which were in a special text- based format, were published (2006 Second Edition) in February 2007. The current TIGER data are available for download since March 31, 2008 by the Census Bureau in shapefile and Geography Markup Language format. This is done inter alia through WFS and WMS servers.

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