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[[Image:US-Census-TIGERLogo.svg|thumb|TIGER logo]]
[[Image:US-Census-TIGERLogo.svg|thumb|TIGER logo]]


'''Topologically Integrated Geographic Encoding and Referencing''', or '''TIGER''', or '''TIGER/Line''' is a format used by the [[United States Census Bureau]] to describe physical and cultural features such as roads, highways, city limits, rivers, and lakes, as well as areas such as [[census tracts]].  TIGER was developed to support and improve the Bureau's process of taking the [[United States Census|Decennial Census]].
'''Topologically Integrated Geographic Encoding and Referencing''', or '''TIGER''', or '''TIGER/Line''' is a format used by the [[United States Census Bureau]] to describe physical and cultural features such as roads, highways, city limits, rivers, and lakes, as well as areas such as [[census tracts]].  TIGER was developed to support and improve the Bureau's process of taking the [[United States Census|Decennial Census]]. Developed in collaboration with the United States Geological Survey during the 1980s, TIGER was the first nationwide digital map of roads, boundaries and water and was initially created for the 1990 Census to modernize the once-a-decade head count. However, its impact has extended well beyond its initial purpose by offering common map data in electronic form that powers today’s geographic information system industry. TIGER still serves as the basemap for many commercial and open-source map projects in very rural areas of the United States.  However, commercial mapping companies now offer newer and more detailed mapping data in urban and high growth areas.


The TIGER files do not contain the census [[demographic]] data, but merely the geospatial/map data. [[GIS]] can be used to merge census demographics or other data sources with the TIGER files to create maps and conduct analysis. TIGER data is available without cost because [[Work of the United States Government|U.S. Government publications]] are required to be released into the [[public domain]].
The TIGER files do not contain the census [[demographic]] data, but merely the geospatial/map data. [[GIS]] can be used to merge census demographics or other data sources with the TIGER files to create maps and conduct analysis. TIGER data is available without cost because [[Work of the United States Government|U.S. Government publications]] are required to be released into the [[public domain]].
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The TIGER/Line shapefile data includes complete coverage of the contiguous United States, [[Alaska]], [[Hawaii]], [[Puerto Rico]], the [[U.S. Virgin Islands]], [[American Samoa]], [[Guam]], the [[Commonwealth of the Northern Mariana Islands]], and the [[Midway Islands]].
The TIGER/Line shapefile data includes complete coverage of the contiguous United States, [[Alaska]], [[Hawaii]], [[Puerto Rico]], the [[U.S. Virgin Islands]], [[American Samoa]], [[Guam]], the [[Commonwealth of the Northern Mariana Islands]], and the [[Midway Islands]].


TIGER includes both land features such as roads, rivers, and lakes, as well as areas such as counties, census tracts, and census blocks.  Some of the geographic areas represented in TIGER are political areas, including state and federally recognized tribal lands, cities, counties, congressional districts, and school districts.  Others are statistical areas, including Metropolitan Statistical Areas (MSA), census tracts, census block groups, and census blocks. [[ZIP Code Tabulation Area]]s (ZCTA) are quasi-statistical areas which attempt to approximate, but do not exactly match, the delivery areas of [[USPS]] [[ZIP code]]s.<ref name="marx">{{cite book |author=Marx, Robert W. |chapter=The TIGER system: automating the geographic structure of the United States Census |title=Introductory Readings in Geographic Information Systems |editor=Peuquet, Donna J. |editor2=Duane Francis Marble |publisher=CRC Press |year=1990 |isbn=0-85066-857-3 |url-access=registration |url=https://archive.org/details/introductoryread0000unse }}</ref>  ZIP codes are not truly areas, but rather a group of deliverable addresses.<ref>See [[ZIP Code#By geography]].</ref> Some or all of an existing ZIP code's addresses may be reassigned to a new ZIP if there is sufficient growth within a given postal ZIP Code. As many as 3% of ZIP codes undergo change each quarter. Thus, the 5-digit ZCTAs are of limited value in areas of growth or change.
TIGER contains both land features such as roads, rivers, and lakes, as well as political and statistical areas such as counties, census tracts, and census blocks.  Some of the political areas represented in TIGER are state and federally recognized tribal lands, cities, counties, congressional districts, and school districts.  Others are statistical areas, including Metropolitan Statistical Areas (MSA), census tracts, census block groups, and census blocks. [[ZIP Code Tabulation Area]]s (ZCTA) are quasi-statistical areas which attempt to approximate, but do not exactly match, the delivery areas of [[USPS]] [[ZIP code]]s.<ref name="marx">{{cite book |author=Marx, Robert W. |chapter=The TIGER system: automating the geographic structure of the United States Census |title=Introductory Readings in Geographic Information Systems |editor=Peuquet, Donna J. |editor2=Duane Francis Marble |publisher=CRC Press |year=1990 |isbn=0-85066-857-3 |url-access=registration |url=https://archive.org/details/introductoryread0000unse }}</ref>  ZIP codes are based on postal delivery routes and may not correspond to municipalities.<ref>{{cite web |url=https://crsreports.congress.gov/product/pdf/IF/IF12132/2 |title=Postal Primer: ZIP Codes and Boundary Review Process |last=Christensen |first=Michelle D |date=14 June 2022 |website=crsreports.congress.gov |publisher=Congressional Research Service |access-date=25 October 2022}}</ref>


ZIP codes are based on postal delivery routes and may not correspond to municipalities.<ref>{{cite web |url=https://crsreports.congress.gov/product/pdf/IF/IF12132/2 |title= Postal Primer: ZIP Codes and Boundary Review Process |last= Christensen |first= Michelle D |date= 14 June 2022 |website= crsreports.congress.gov|publisher= Congressional Research Service|access-date= 25 October 2022}}</ref>
==Future==
TIGER data published through February 2007 (2006 Second Edition) were in a custom [[ASCII]] format formally known as TIGER/Line files. In 2008, data in [[shapefile]] format was published. Shapefiles are not [[Topology|topological]], therefore they may contain sliver polygons when comparing TIGER/Line boundaries with other TIGER features. This mismatch was not inherent when the census TIGER/Line files were released in the original ASCII format. The Census Bureau has been offering TIGER/Line data as Geodatabases since 2017, and open-source [[GeoPackage|Geopackages]] since 2024. These formats can maintain topological relationships between themes or 'layers'.


==Future==
Additionally, the Census Bureau has made TIGER data available through [[Web Map Service|WMS]] servers known as [https://tigerweb.geo.census.gov/tigerwebmain/TIGERweb_main.html TIGERweb].<ref>{{Cite web |title=The Future of TIGER/Line® |url=http://www.census.gov/geo/www/tiger/future/future_tl.html |last=<!--Not stated--> |date=2006-07-20 |url-status=dead |archive-url=https://web.archive.org/web/20070306011947/http://www.census.gov/geo/www/tiger/future/future_tl.html |archive-date=2007-03-06 |access-date=2007-03-04 |website=[[U.S. Census Bureau]]}}</ref>
TIGER data published through February 2007 (2006 Second Edition) were in a custom text-based format formally known as TIGER/Line files. In 2008, data in [[shapefile]] format was published.  Please note that shapefiles are not topological, therefore may create slivers when comparing TIGER/Line boundaries. This mismatch was not possible when the census TIGER files were available in ASCII format that was topological unlike shapefiles. The Census Bureau has made the data available through [[Web Map Service|WMS]] servers.<ref>[https://www.census.gov/geo/www/tiger/future/future_tl.html Future of TIGER data], U.S. Census Bureau</ref> The data forms a base for [[OpenStreetMap]] in the US, and also was used for the initial import of US map data into the Waze navigation system.


==References==
==References==
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==External links==
==External links==
{{commons category|United States Census TIGER maps}}
{{commons category|United States Census TIGER maps}}
* [https://tigerweb.geo.census.gov/tigerwebmain/TIGERweb_main.html TIGERweb Mapping Service]
* {{Official website|https://tigerweb.geo.census.gov/tigerwebmain/TIGERweb_main.html}}
* [https://www.census.gov/programs-surveys/geography/about/training/25-years-tiger.html "Celebrating 25 Years of TIGER"], a history of the database


[[Category:GIS file formats]]
[[Category:GIS file formats]]
[[Category:United States Census Bureau geography]]
[[Category:United States Census Bureau geography]]

Latest revision as of 18:14, 16 December 2025

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File:US-Census-TIGERLogo.svg
TIGER logo

Topologically Integrated Geographic Encoding and Referencing, or TIGER, or TIGER/Line is a format used by the United States Census Bureau to describe physical and cultural features such as roads, highways, city limits, rivers, and lakes, as well as areas such as census tracts. TIGER was developed to support and improve the Bureau's process of taking the Decennial Census. Developed in collaboration with the United States Geological Survey during the 1980s, TIGER was the first nationwide digital map of roads, boundaries and water and was initially created for the 1990 Census to modernize the once-a-decade head count. However, its impact has extended well beyond its initial purpose by offering common map data in electronic form that powers today’s geographic information system industry. TIGER still serves as the basemap for many commercial and open-source map projects in very rural areas of the United States. However, commercial mapping companies now offer newer and more detailed mapping data in urban and high growth areas.

The TIGER files do not contain the census demographic data, but merely the geospatial/map data. GIS can be used to merge census demographics or other data sources with the TIGER files to create maps and conduct analysis. TIGER data is available without cost because U.S. Government publications are required to be released into the public domain.

Coverage

The TIGER/Line shapefile data includes complete coverage of the contiguous United States, Alaska, Hawaii, Puerto Rico, the U.S. Virgin Islands, American Samoa, Guam, the Commonwealth of the Northern Mariana Islands, and the Midway Islands.

TIGER contains both land features such as roads, rivers, and lakes, as well as political and statistical areas such as counties, census tracts, and census blocks. Some of the political areas represented in TIGER are state and federally recognized tribal lands, cities, counties, congressional districts, and school districts. Others are statistical areas, including Metropolitan Statistical Areas (MSA), census tracts, census block groups, and census blocks. ZIP Code Tabulation Areas (ZCTA) are quasi-statistical areas which attempt to approximate, but do not exactly match, the delivery areas of USPS ZIP codes.[1] ZIP codes are based on postal delivery routes and may not correspond to municipalities.[2]

Future

TIGER data published through February 2007 (2006 Second Edition) were in a custom ASCII format formally known as TIGER/Line files. In 2008, data in shapefile format was published. Shapefiles are not topological, therefore they may contain sliver polygons when comparing TIGER/Line boundaries with other TIGER features. This mismatch was not inherent when the census TIGER/Line files were released in the original ASCII format. The Census Bureau has been offering TIGER/Line data as Geodatabases since 2017, and open-source Geopackages since 2024. These formats can maintain topological relationships between themes or 'layers'.

Additionally, the Census Bureau has made TIGER data available through WMS servers known as TIGERweb.[3]

References

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External links

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  • "Celebrating 25 Years of TIGER", a history of the database