Geologic data from the geologic map of the Spokane 1:100,000-scale quadrangle compiled by Joseph (1990) were entered into a geographic information system (GIS) as part of a larger effort to create regional digital geology for the Pacific Northwest. The map area is located in eastern Washington and extendds across the state border into western Idaho.
To create a digital geologic map of the Spokane 1:100,000-scale quadrangle that is readily available to the public/
We wish to thank Robert E. Derkey and J. Eric Schuster of the Washington Division of Geology and Earth Resources for their part in initiating this project, and for providing the original stable-base mylar and the funding for it to be scanned.
Joseph (1990) was the sole source of geologic data used to create the digital map.
The overall accurace of the digital geologic map is probably no better than +/- 70 meters.
Source_Citation_Abbreviation:Joseph (1990) Source_Contribution:Sole source of geologic data
The original stable-base mylar of the geologic linework for the 1:100,000-scale geologic map was electronically scanned to create a raster digital image. The resulting TIFF-formate image (600 do per inch resolution) was registered to a UTM grid and rectified in Arc/Info. The rectified raster image was then converted to a vector GIS layer using the GRIDLINE vectorization tool included in the Arc/Info GRID extension. Subsequent clean-up of the vector layer was done in PC Arc/Info. Linework for water bodies that obscured geologic contact was converted from digital line graph (DLG) formate files to PC Arc/Info so as to delineate discrete geologic unit boundaries. The resulting geologic map was attributed, converted to Arc/Info, and then plotted and compared to the original mylar to check for digitizing and attributing errors.
Process_Description:Creation of original metadata record Process_Date:20000728 Process_Contact:
Entity_Type_Label:SPOK100K.AAT Entity_Type_Definition:Linear features on geologic map Entity_Type_Definition_Source:OFR-98-115
Numeric code used to identify type of linear feature. Linecodes <100 are used for contacts and boundaries which are descripbed in the SPOK100K.CON file. Linecodes >100 are <60 represent structural features which are described in the SPOK100K.STR file. Linecodes >800 represent linear geologic units which are described in the SPOK100K.LGU file.
This report is preliminary and has not been reviewed for conformity with US Geological Survey editorial standards or with the North American Stratigraphic Code. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the US Government.
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