STATE-FEDERAL STANDARDS FOR THE NATIONAL GEOLOGIC MAP DATABASE
Because of the mandate's broad scope, we use a phased, incremental approach to design the Database. This approach gives us the necessary time to build consensus and expertise among the Database designers in the State geological surveys and the USGS. Furthermore, it helps us to more effectively consider and respond to evolving technology and user needs.
We started by creating a Map Catalog containing bibliographic information on more than 61,000 geoscience map products, and a geologic names lexicon (GEOLEX). We recently opened the prototype site for our Image Library of geologic maps; there, users can view high-resolution images of maps online, and read the detailed descriptions that accompany them. These databases are available at http://ngmdb.usgs.gov/.
Our long-term goal is to develop a Web-accessible, distributed database of vector-based geologic map information created and served by the numerous project partners. For this database to be most useful to the public, it is imperative that our data structure be flexible and that our science terminology encompass a rich, comprehensive set of descriptions for the physical properties of geologic materials. Working with other U.S. and Canadian agencies, we are developing standards for a conceptual data model, lithologic terminology, locational accuracy, and map symbology. We are designing the database through a series of prototypes, iteratively testing the standards and evolving our ideas on database design for a system that will be implemented in different computer hardware and software environments. NGMDB standards and related information can be found at http://ncgmp.usgs.gov/ngmdbproject/.