Rectified Images of Selected Geologic Maps in the Northern Rockies Area, Idaho, Montana, Washington, and Wyoming

Selected geologic maps covering parts of the Northern Rocky Mountains and
adjacent areas were converted to raster images and georeferenced (rectified)
for use in a geographic information system (GIS). These rectified images were
created for the purpose of visually comparing published geologic maps with
other geospatial information. However, they cannot be queried or used for
spatial analysis thus limiting their use in a GIS. The 42 georeferenced images
included in this report range in scale from 1:250,000 to 1:100,000.

Tagged Image Format (TIFF) images of the maps were generated by scanning an
original paper map or converting previously published Portable Document Format
(PDF) images or Encapsulated Post-Script (EPS) files. To reduce file size and
minimize image overlap, the TIFF images were cropped, and then rectified using
ArcMap 8 and converted to MrSID images. Information in the explanation and
cross sections can be viewed in un-rectified images of the original
publications that are included with this report. In addition, the text in the
map unit description along with the unit name, map label, and a citation are
organized in a searchable PDF file.

[Summary provided by the USGS.]