Print this pageAbstract: Development
of Digital Geologic Map Databases from Published Geologic 
Maps
: Historic
Preservation or Information Collection?
ROSS, JORGINA A. and ELIZABETH L. CROUSE
In database development,
understanding why is essential to the proper choice of how. Increased use
of computers in all phases of development of regional exploration programs
and analysis of local prospects has increased the demand for high quality
digital maps of surface geology. Large sums of money are being invested
by state and federal agencies developing digital geologic map databases.
A large part of this investment has focused on new field mapping in areas
where published geologic maps were unavailable or deemed inadequate. In
these programs, digital databases are usually derived from large scale
(1:24,000) base maps developed by the project geologist. The slow pace
of database development from new field mapping, combined with budget constraints,
requires that more cost-effective methods be used wherever possible to
develop statewide or national databases.
Where good quality published
geologic maps are available, their conversion to digital form has been
seen as a solution to the cost problem. Technology and dollars have focused
on the precise preservation of geologic patterns printed on these maps.
Given the cartographic generalization inherent in the smaller scales (1:63,360
or less) at which most of the maps have been published, the usefulness
of the results is seriously limited. A simple but innovative procedure,
requiring only modest interpretation of published geologic maps in relation
to the topographic model presented on corresponding 1:24,000 scale maps,
maximizes the capture of information presented in published geologic maps.
The resulting digital databases compare favorably with the results of new
field mapping, with significant reductions in development time and labor
costs.
AAPG Search and Discovery Article #90944©1997 AAPG Mid-Continent Section Meeting, Oklahoma City, Oklahoma
