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 Geographic base file (GBF) A generic term for a computer file of geographic attributes of an area (such as street names, address ranges, geographic codes, hydrography, railroads). See also Address Coding Guide, GBF/DIME-File, TIGER data base, TIGER System.

Geographic code One or more alphanumeric symbols used to identify a legal, administrative, or statistical entity. See also Address Coding Guide, Federal Information Processing Standards, GBF/DIME-File, geocode, geographic base file, geographic data base, TIGER data base, TIGER System.

Geographic data base A computer-readable data base, the primary structure of which includes geographic codes and/or coordinates. The GBF/DIME-File and TIGER data base are geographic data bases used by the Census Bureau to conduct the 1980 and 1990 censuses, respectively. See also Address Coding Guide, GBF/DIME-File, TIGER data base, TIGER System.

Geographic entity A geographic unit of any type—legal, administrative, or statistical. See also geographic code, geographic data base, geographic hierarchy.

Geographic hierarchy A system of relationships among geographic entities in which each geographic entity (except the smallest one) is subdivided into lower-order units that in turn may be subdivided further. For example, States are subdivided into counties, which are subdivided into county subdivisions. Most 1990 census reports and STFs present data in all or part of the hierarchical sequence: United States, region, division, State, county, county subdivision, place (incorporated/census designated), place part or remainder of county subdivision, census tract/block numbering area (or part), block group (or part), and block. See also geographic code, geographic data base, part.

Geographic Identification Code Scheme (GICS) A detailed listing of the geographic codes, associated names, and attributes that the Census Bureau used to identify the various legal, administrative, and statistical geographic entities of the United States in a specific census. See also administrative entity, legal entity, statistical entity. G-26Glossary