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The Choteau geologic map database was initially prepared by Jef Silkwood (U.S. Forest Service) from the geologic map by Mudge and others (1982). These preliminary digital files were transferred to the U.S. Geological Survey (USGS) in 1999. Robert J. Miller (USGS) merged the geology (lines and polygons) and structure (lines) files into a single topological ArcInfo dataset. Steven R. Munts (contractor) digitized additional structural features (folds) from Mudge and others (1982). The digital files were then augmented with an interim geologic map data model (data base), further attributed and edited, and then plotted and compared to the published geologic map to check for digitizing and attribute errors. All processing by the U.S. Geological Survey was done in ArcInfo version 7.2.1 installed on a Unix-based Sun Ultra workstation.
Pamela D. Derkey and Robert J. Miller (both of the USGS) provided technical assistance with the geologic systems data model, metadata, digital documentation, and map projections; Steven R. Munts (contractor) digitized new linework, edited digital files, combined existing data sets, built look-up tables, and prepared the composite dataset.
This dataset was developed to provide geologic map GIS of the Choteau 1:250,000 quadrangle for use in future spatial analysis by a variety of users. These data can be printed in a variety of ways to display various geologic features or used for digital analysis and modeling. This database is not meant to be used or displayed at any scale larger than 1:250,000 (e.g. 1:100,000 or 1:24,000).
Are there legal restrictions on access or use of the data?Access_Constraints: none
Use_Constraints:This digital database is not meant to be used or displayed at any scale larger than 1:250,000 (e.g. 1:100,000).
Any hardcopies utilizing these data sets shall clearly indicate their source. If the user has modified the data in any way they are obligated to describe the types of modifications they have performed on the hardcopy map. User specifically agrees not to misrepresent these data sets, nor to imply that changes they made were approved by the US Geological Survey.
The U.S. Geological Survey (USGS) provides these geographic data "as is". The USGS makes no guarantee or warranty concerning the accuracy of information contained in the geographic data. The USGS further makes no warranties, either expressed or implied as to any other matter whatsoever, including, without limitation, the condition of the product, or its fitness for any particular purpose. The burden for determining fitness for use lies entirely with the user. Although these data have been processed successfully on computers at the USGS, no warranty, expressed or implied, is made by the USGS regarding the use of these data on any other system, nor does the fact of distribution constitute or imply any such warranty.
In no event shall the USGS have any liability whatsoever for payment of any consequential, incidental, indirect, special, or tort damages of any kind, including, but not limited to, any loss of profits arising out of use of or reliance on the geographic data or arising out of the delivery, installation, operation, or support by USGS.
This digital geologic map GIS of the Choteau 1:250,000 quadrangle, Montana, is not meant to be used or displayed at any scale larger than 1:250,000 (e.g. 1:100,000 or 1:24,000).
| Data format: | Geologic units and structural features as polygons, arcs, and points. in format ARCE (version 7.2.1) Size: 13.2 |
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| Network links: |
http://pubs.usgs.gov/imap/i1300/chot250k.tar.Z |
