Programs and Services

Digital Geologic Mapping and GIS Lab

Digital Geologic Map Data Model

Currently many groups are working on geologic map data model design. One of the best known of these to date is the Geological Survey of Canada, U.S. Geological Survey and Association of American State Geologists effort: NADM Conceptual Model 1.0— A Conceptual Model for Geologic Map Information

Technical working groups under the the North American digital geologic map data model Steering Committee have begun to solve some of the thorny issues involved in developing a workable North American Data Model (NADM) for geologic mapping: Specifically science language for earth materials. For more detail and downloadable products go to

The Idaho Geological Survey has been producing geologic maps digitally since 1989. The Idaho Survey began to capture a database of basic geologic attributes associated with each geologic feature on a map in 1992 as part of its map digitizing process. Beginning in 1996 metadata, or information about the map and its sources, has been input for each 30 x 60 minute geologic map compilation. These attributed spatial data can be used in a Geographic Information System (GIS) to perform simple queries or analyses. However, to receive consistent and meaningful answers to complicated questions about the geology on a digital map, requires yet another database of map information derived from the map legend.

Taken together, the spatial map data, map legend, and metadata comprise a digital geologic map database. The design of these data sets and how they relate to one another to supply reasonable interpretations of the map is a digital geologic map data model.

Idaho Survey's Data Model

The Idaho Geological Survey's Digital Geologic Map Data Model, Version 2.1, is an applied variant model based on the earlier proto-model NADM 4.3. The Idaho Survey model is designed for use in ArcView GIS. It is currently being applied to all digital geologic map compilation data (30 x 60 minute tiles).


To learn more, download the current version of the Idaho Survey's data model documentation:
Title Download/View
Digital Geologic Map Data Model Structure and Connection Diagram View
Idaho Geological Survey's data model documentation View
Comparison of the Idaho model with NADM 4.3 View


Last update 2-8-2005


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