Introduction

In the U.S. and Canada, national geologic map databases are being designed and, in prototype form, constructed. These database systems simultaneously address two basic needs: improving the efficiency of routine information handling within an agency, and promoting both traditional and non-traditional uses of geologic information within and outside the agency. In North America, for example, three major systems or initiatives exemplify this approach: 1) the Canadian Geoscience Knowledge Network (CGKN), a cooperative initiative to link the public geoscience data providers in Canada, led by the Geological Survey of Canada (GSC); 2) the U.S. National Geologic Map Database project (NGMDB), a Congressionally-mandated database and standards-development effort based on collaboration between the Association of American State Geologists (AASG) and the U.S. Geological Survey (USGS); and 3) GeoInformatics Network (GEON), a proposed network of U.S. academic geoscience databases.).

In 1999 and 2000, drawing on experiences from the Canadian and United States initiatives above, the authors undertook to design and build a prototype NGMDB database for central Kentucky, a state well advanced in geological mapping. This report describes the object-oriented data model upon which this prototype was founded, and briefly describes the implementation in the GE-Smallworld database environment. We believe that it is principally through such prototypes that the geoscience community will evolve to a stable set of modeling concepts and implementation approaches that effectively manage digital geologic map information.

At present, however, data modeling of geologic map information is not a mature discipline. Both the data model and the database design presented here are experimental; they were built as prototypes, not formal proposals, and so lack completeness and polish by comparison to some other publicly-accessible database designs for the geosciences. On the other hand, these activities have stimulated additional, advanced data modeling beyond that described here, particularly as reported in Hastings and Brodaric (2001) and Brodaric and Hastings (2002), portions of which are excerpted here for ease of reference. In sum, this is a progress report on geological data modeling in the NGMDB generally, as well as a final report on the prototype for central Kentucky.