As the nation's primary Federal earth-science, factfinding and research agency, the U. S. Geological Survey (USGS) provides cartographic and natural resource information to many users to aid in planning and decision-making. Users of the data, both inside and outside the USGS, have become more and more sophisticated in their applications. As a consequence, scientists at the USGS are embracing computer technology as an essential element of their data gathering and production activities. Now, much of that cartographic information is available in computer-compatible form on magnetic tape from USGS national digital cartographic data bases.