2008 TIGER/Line Shapefiles Technical Documentation Chapter 1: Introduction 1.1 What are 2008 TIGER/Line Shapefiles? The 2008 TIGER/Line Shapefiles are extracts of selected geographic and cartographic information from the U.S. Census Bureau's Master Address File/Topologically Integrated Geographic Encoding and Referencing (MAF/TIGER) database. The MAF/TIGER database was developed at the Census Bureau to support the mapping and related geographic activities required for implementation of the decennial and economic censuses and sample survey programs. Geographic base linear, area, and point features such as streets, railroads, rivers, lakes, and geographic area boundaries are represented in the files, as well as the polygons that make up the legal and statistical geographic areas for which the Census Bureau tabulates data. The files also contain attribute information about these features, such as names, the type of feature, address ranges for most streets, the geographic relationship to other features, and other related information. The shapefiles include information for the fifty states, the District of Columbia, Puerto Rico, and the Island Areas (American Samoa, the Commonwealth of the Northern Mariana Islands, Guam, and the Virgin Islands of the United States). The TIGER/Line Shapefiles contain attribute data only and do not include mapping software. They are designed for use with geographic information system (GIS) software. The TIGER/Line Shapefiles do not contain demographic data from any census or survey, but do include the geographic entity codes, which provide a link between the Census Bureau’s demographic data and the TIGER/Line Shapefiles. 1.2 What is the MAF/TIGER database? The Census Bureau’s MAF/TIGER(R) database contains the geographic and address information required to support the decennial census and many other census surveys and programs. The design of the MAF/TIGER database adapts the theories of topology, graph theory, and associated fields of mathematics to provide a disciplined, mathematical description for the geographic structure of the United States and its territories. The topological structure of the MAF/TIGER database defines the location and relationship of streets, rivers, railroads, and other features to each other and to the numerous geographic entities for which the Census Bureau tabulates data from its censuses and sample surveys. It is designed to minimize the possibility of coverage gaps or conflicting coverage overlaps. The building of the MAF/TIGER database involved a variety of encoding techniques such as automated map scanning, manual map digitizing, standard data keying, and sophisticated computer file matching. The goal was to provide automated access to, and retrieval of, relevant geographic information about the United States and its territories. To enable the public to use much of the information in the MAF/TIGER database in a GIS or for other geographic applications, the Census Bureau releases periodic extracts of the database. The 2008 TIGER/Line Shapefiles are the second extracts in shapefile format. The first extracts, the 2007 TIGER/Line Shapefiles, were released in March, 2008. Prior to that release, numerous versions of the TIGER/Line files were made available, beginning with the 1990 TIGER/Line files. The Redistricting Census 2000 version of the TIGER/Line files, which was the official version of the TIGER/Line files, was delivered to the designated recipients under Public Law 94-171 and to redistricting officials in the District of Columbia and Puerto Rico. The Census 2000 version of the TIGER/Line files originally was produced to support the Census 2000 Summary File 1 (SF 1) data files. The Census Bureau released the Urbanized Area (UA) Census 2000 version of the TIGER/Line files to support the Census 2000 Urban Areas Program. The Census Bureau also released the 108th Congressional District Census 2000 TIGER/Line files. More recent releases include one version of the TIGER/Line files for 2002 and 2003 and both first and second editions for 2004, 2005, and 2006. More information on previous versions of TIGER/Line files can be found at http://www.census.gov/geo/www/tiger/index.html. 1.3 Relationship of the TIGER/Line Shapefiles to Census Statistical Data What makes the MAF/TIGER extract products particularly valuable in the GIS environment and to the data user community is the ability to create a direct linkage between data from Census 2000, the American Community Survey, the Economic Census, or other survey and population estimate data and the geographic areas in the MAF/TIGER database extracts. The digital description in the MAF/TIGER database of the nation’s legal and statistical entities includes Federal Information Processing Standards (FIPS) codes and, for selected geographic entities, Census Bureau codes and American National Standards Institute (ANSI) codes so that entities can be easily matched and linked with data from Census 2000 and subsequent programs and censuses. 1.4 2008 TIGER/Line Shapefile Geography The 2008 TIGER/Line Shapefiles are available in multiple vintages to enable data users to match geography of the appropriate vintage with the data they are linking to the shapefiles. The following is an explanation of the vintages available in the 2008 TIGER/Line Shapefiles. Table 1.4.1 shows the vintages available for each shapefile or relationship file. Census 2000 geography is defined as the geographic extent of legally defined geographic areas (boundaries of governmental units) or statistical areas in effect on January 1, 2000. This vintage enables users to work with Census 2000 data using boundaries as they existed in 2000. The Census Bureau has not systematically updated the inventory or boundaries of statistical areas since 2000; however, changes to legal areas may affect statistical areas. Current geography is defined as the latest version of the geographic extent of legally defined geographic areas as reported, generally reflecting the boundaries of governmental units in effect as of January 1, 2008, or legal and statistical area boundaries that have been adjusted and/or corrected since Census 2000. This vintage enables users to see the most current boundaries of governmental units so that they match the 2008 American Community Survey data or 2008 population estimates. 2007 Economic Census geography is defined as the version of the geographic extent of legally defined geographic areas legally in effect on January 1, 2007. The Economic Census is the major economic statistical program of the United States, and it provides a detailed portrait of the nation’s economy once every five years. The geographic entities used in an Economic Census can differ from those used in decennial censuses. The boundaries used for geographic entities for the 2007 Economic Census are those reported to the Census Bureau through the Boundary and Annexation Survey to be legally in effect on January 1, 2007. Table 1.4.1: 2008 TIGER/Line Shapefile Layers by Vintage Layer 2000 Current Economic Census 108th Congressional District (Congress elected in 2002) X 110th Congressional District (Congress elected in 2006) X 1-Percent Public Use Microdata Area X 5- or 10-Percent Public Use Microdata Area X 3-Digit ZIP Code Tabulation Area X 2002* 5-Digit ZIP Code Tabulation Area X 2002* Address Range-Feature Name Relationship File X Address Ranges Relationship File X Alaska Native Regional Corporation X X All Lines X American Indian Tribal Subdivision X X American Indian/Alaska Native/Native Hawaiian Area X X Area Hydrography X Area Landmark X Block X X Block Group X Census Tract X Combined New England City and Town Area X Combined Statistical Area X Commercial Region X Consolidated City X X X County and Equivalent X X X County Subdivision X X Elementary School District X X Feature Names Relationship File X Metropolitan Division X Metropolitan/Micropolitan Statistical Area X Military Installation X New England City and Town Area X New England City and Town Area Division X Other Identifiers Relationship File X Place X x X Point Landmark X Secondary School District X X State and Equivalent X x X State Legislative District—Lower Chamber X X State Legislative District—Upper Chamber X X Subbarrio X X Topological Faces (2-Cells With All Geocodes) Relationship File X Topological Faces-Area Hydrography Relationship File X Topological Faces-Area Landmark Relationship File X Traffic Analysis Zone X Unified School District X X Urban Areas x Corrected 2000** Urban Growth Area X X Voting District X * An updated version of the ZCTAs reflecting a 2002 vintage is the most current file available. ** This file contains corrections to the Census 2000 urbanized areas and urban clusters. These corrections were announced in 2002, and are the official urban areas for Census 2000. For more information, please see the “Urban Areas” section in Chapter 3. 1.5 2008 TIGER/Line Shapefile Legal Disclaimers No warranty, expressed or implied, is made with regard to the accuracy of the data in the TIGER/Line Shapefiles, and no liability is assumed by the U.S. Government in general, or the Census Bureau specifically, as to the positional or attribute accuracy of the data. The boundary information in the TIGER/Line Shapefiles is 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. TIGER(R) and TIGER/Line(R) are registered trademarks of the Census Bureau and ZCTA(TM) is a trademark of the Census Bureau. As such, these names cannot be used as or within the proprietary product names of any commercial product including or otherwise relevant to Census Bureau data, and may only be used to refer to the nature of such product. The Census Bureau requests that any repackaging of the TIGER/Line Shapefile data, documentation, and other files accompanying it for distribution include a conspicuously placed statement to this effect on the product's cover, the first page of the website, or elsewhere of comparable visibility. Further, Census Bureau trademarks, when used in reference to the nature of the product, should be accompanied by the (R) (registered) symbol or (TM) symbol, where convenient. 1.6 Questions and Contact Information If you obtained the TIGER/Line Shapefiles directly from the Census Bureau and need further information concerning the content of the files, contact the Geographic Products Branch, Geography Division, Census Bureau, Washington, DC 20233-7400. The telephone number is (301) 763-1128. The e-mail address is geo.tiger@census.gov. For information concerning the subject matter and contents of TIGER/Line Shapefiles obtained from a source other than the Census Bureau, contact that source.