PROTOTYPE DATABASE DEVELOPMENT LEADING TO A NATIONAL GEOLOGIC MAP DATABASE

The efficiency and capability to utilize geospatial data depends upon the structure and language used to organize diverse data sets, in short a data model. The National Geologic Map Database Project (NGMDB) of the U.S. Geological Survey (USGS) has been working with national and international partners to implement the evolving North American Data Model Steering Committee (NADMSC) data model. NGMDB has developed a number of prototype databases using object-relational GIS software to reach the functionality demanded by the model, to provide a seamless database of geologic map data; to provide versions of the data for publishing, investigation and analysis; and to provide web access to deliver such data. Results to date are encouraging and provide the following benefits over more conventional GIS approaches. Iterative changes to the underlying data model do not change the data already in place. Implementation of dynamic map generation based on feature generalizations is straightforward. Web access of the database allows rapid access, modification, query and efficient analysis. Geologic map features are referenced by geologic concepts primarily rather by the geometry of the feature. Some problems encountered remain demanding. Geologic language tables to accompany the database have been difficult to develop, a list of routine queries for use with the database have been slow to evolve, and the routine importation of multiple data formats from the same GIS software has not been implemented.