Geologic Database for Digital Geology of California, Nevada, and Utah, an Application of the North American Data Model: Open-File Report 2003-135

The original Geologic Map of Utah (Hintze, 1980) was published with eight separate stratigraphic columns and descriptions for differing regions of the state map. These regions were depicted on a very small scale index map in that report. No previously published digital report has included this information. The authors of this report have included these separate stratigraphic descriptions in the databases, for users who may want to use them. However, users will have to perform some extra GIS operations with the data included in this report to incorporate this information. This publication is distributed with a spatial dataset containing points that describe the region for each polygon in the user-supplied Digital Geologic Map of Utah (Hintze et al, 2000). These points were created by digitizing the region index map from the original state map, then performing a GIS intersect operation with the map of Hintze, et al. The resulting region boundaries were then removed from the database, resulting in the original state geologic map polygons with a region code. Because the index map was such a small scale, geologic polygons near the region boundaries had to be evaluated and manually assigned a correct region code. Units with ambiguous or indeterminate region assignments were not assigned to a region and therefore are attributed with the state-wide map unit.