The Census Bureau's Geography Division is developing a digital geographic and cartographic data file, the TIGER file, so that it can automate most of its support operations for the 1990 Decennial Census. A cornerstone of this project is an historic agreement with the US Geological Survey (USGS). Under the agreement, the USGS is accelerating its production of 1:100,000-scale maps covering the lower 48 states and then producing raster scanned digital files of selected data appearing on these maps. The Census Bureau is assigning geographic attributes, such as feature names and classification codes, and geographic area codes, to the points, lines, and areas represented in these files. The Census Bureau then will be able to produce high quality maps, assign addresses and selected major facilities to the correct geographic entities, by using the TIGER file. For the more than 300 metropolitan areas in the country, the Census Bureau is using digitized GBF/DIME-files to build the TIGER file. Although these files lack the absolute coordinate accuracy of the USGS files, they already contain feature names, address ranges, and 1980 geographic area codes. The Census Bureau used the GBF/DIME-files when it assigned individual census questionnaires (that is then mailed out) to the correct 1980 census tract and block number. The Census Bureau evaluated these files before the 1980 census and determined a nationwide geocoding error rate of 3.5 percent at the block level. Given this very low error rate and the limited time available to develop the TIGER file, the Geography Division concluded that it could not complete a merger of the geographic information in the GBF/DIME-files with the cartographic information in the USGS files this decade. Instead, the Geography Division has begun updating the GBF/DIME-files to reflect current feature patterns and many new address ranges; it then will reformat these files into the TIGER file structure and substitute them for their USGS file counterparts in metropolitan areas to create the nationwide TIGER file.