History

Notable Alumni

James Corbett

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A 1968 Census Bulletin article on the
development of the Dual Independent
Map Encoding System.

Based on the principles of map topology, James Corbett, a mathematician with the U.S. Census Bureau's Statistical Research Division developed Dual Independent Map Encoding (DIME) to resolve problems researchers were having while experimenting with Geographic Base Files (GBF) research. In 1967, researchers were attempting to convert analog maps into numerically encoded renderings using data from the 1967 pretest of mailout/mailback procedures in New Haven, CT, but found the process to be bogged down by redundant operations. Corbett introduced the basic ideas of the vector paradigm to the programmers, thus creation of the DIME protocol.

Within DIME, intersections, streets, and blocks became analogous to points, lines, and polygons, respectively. The latter group of objects would come to represent the essence of vector data, a structure rooted in Cartesian coordinate geometry. DIME also incorporated the ability to edit topology, a term used to describe the geometric relationships between vector objects.

Based on the principles of map topology, Corbett's innovation laid the groundwork for thematic mapping of census data. GBF-DIME files were then digitized for U.S. cities during the 1970s. These files later became key components of the Census Bureau's Topologically Integrated Geographic Encoding and Referencing (TIGER) system.