The Geologic Mapping Act requires that a National Geologic Map Database (NGMDB) be designed and built by the U.S. Geological Survey (USGS), in cooperation with the Association of American State Geologists (AASG). The Act notes that the NGMDB is intended to serve as a "national archive" of geologic maps, to provide the information needed to address various societal issues. This project is, emphatically, a collaborative effort supported by extensive, open discussion with the geoscience community. In mid-1995, the general stipulations in the Act were addressed in the proposed design and implementation plan developed by the USGS and AASG. Because many maps are not yet in digital form and because many organizations produce and distribute geologic maps, it was decided to develop the NGMDB in several phases.

The first and most fundamental phase is a comprehensive, searchable catalog of all geoscience maps in the United States, in either paper or digital format. The users, upon searching the NGMDB catalog and identifying the map(s) they need, are linked to the appropriate organization for further information about how to procure the map. The map catalog presently is supported by two databases developed under the NGMDB project: 1) GEOLEX, a searchable geologic names lexicon; and 2) Geologic Mapping in Progress, which provides information on current mapping projects.

The second phase of the project focuses on public access to digital geoscience maps, and on participation in the development of U.S. and North American digital map standards and guidelines needed to improve the utility of those digital maps. The third phase, now under development through a series of prototypes, is an online, "living" database of geologic map information at various scales and resolutions. Information can be found at http://ncgmp.usgs.gov/ngmdbproject. The NGMDB is being designed to be compatible with a national geoinformatics information network.