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: