Geographic Base File/Dual Independent Map Encoding (GBF/DIME), 1980 (ICPSR 8378)

Published: Jan 12, 2006

Principal Investigator(s):
United States Department of Commerce. Bureau of the Census

Version V1

A Geographic Base File is a map in machine-readable form, and Dual Independent Map Encoding is the method used for this collection to encode map features in data files. These files have been created for most metropolitan areas. GBF/DIME does not contain individual house addresses, names, or other means of identifying individuals, and it does not contain statistical information. This collection provides a means to structure, compare, and display data, and relate this information to small geographic areas. ICPSR also has the Special Program Information Tape (SPIT) produced by the Census Bureau (See ICPSR 8372), which contains several computer programs designed for use with the GBF/DIME files.

United States Department of Commerce. Bureau of the Census. Geographic Base File/Dual Independent Map Encoding (GBF/DIME), 1980. Ann Arbor, MI: Inter-university Consortium for Political and Social Research [distributor], 2006-01-12.

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1978 -- 1980

The files are ordered by SMSA and MSA code numbers, with one file per area. The same documentation is used for both SMSA and MSA files. Each record within a file identifies a segment of a map feature by its node points, address ranges, and geographic units (blocks, census tracts, places, counties). Records are included for non-street map features such as railroads, streams, and political boundaries, as well as for streets. Node points identify the intersections, directions changes, and terminations of these features.

These geographic reference files cover the urbanized core of 278 Standard Metropolitan Statistical Areas (SMSAs) for which files were developed or updated for the 1980 Census. The collection also contains Metropolitan Statistical Area (MSA) data for 47 selected MSAs. The remaining MSA files are forthcoming and more may be prepared in the future.

program source code



2006-01-12 All files were removed from dataset 398 and flagged as study-level files, so that they will accompany all downloads.


  • Data in this collection are available only to users at ICPSR member institutions.

  • The citation of this study may have changed due to the new version control system that has been implemented.
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