Recent updates to the data:
In March 2004 edition 1.0 of the data set was transitioned to storage in an Oracle RDBMS using the ArcSDE geodatabase model. The result (this version) is designated Edition 20040331.
Illinois State Geological Survey, 1996, Bedrock Geology of Illinois - Geologic Units: ISGS GIS Database GISDB_BEDGEO.IL_Geologic_Units_500K_1967_Py, Illinois State Geological Survey, Champaign, Illinois.
Willman, H. B. , Frye, John C. , Simon, Jake A. , Clegg, Kenneth E. , Swann, D. H. , Atherton, Elwood, Collinson, Charles, Lineback, Jerry, and Buschbach, T. C. , 1967, Geologic Map of Illinois: Geologic Maps Geologic map of Illinois 1967 edition, Williams and Heintz Map Corp., Capitol Heights, MD, USA.
This is a Vector data set. It contains the following vector data types (SDTS terminology):
Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.000001. Longitudes are given to the nearest 0.000001. Latitude and longitude values are specified in Decimal degrees.
The horizontal datum used is North American Datum of 1983.
The ellipsoid used is Geodetic Reference System 80.
The semi-major axis of the ellipsoid used is 6378137.000000.
The flattening of the ellipsoid used is 1/298.257222.
Sequential unique whole numbers that are automatically generated.
Coordinates defining the features.
These data can be used for any project which requires bedrock data at a scale of 1:500,000. This data should not be used at a scale larger than 1:500,000. Not suitable for site specific work.The data are not appropriate as a geodetic, legal or engineering base. The data set was not and is not intended as a substitute for surveyed locations, such as can be determined by a registered Public Land Surveyor. Although useful in a GIS as a reference base layer for maps, the data set has no legal basis in the definition of boundaries or property lines.
H. B. Willman, John C. Frye, Jake A. Simon, Kenneth, 1967, Geologic Map of Illinois: ISGS map same as title, Williams and Heintz Map Corp., Capitol Heights, MD.
The features were imported into the ISGS SDE enterprise database following steps outlined in ISGS procedure GISDB_0009.
Metadata updated.
Person who carried out this activity:
The published paper geological map from the ISGS was the source for feature attributes. Attribute code assignments were checked by three individuals and are believed to fully representative of the source document.
Horizontal positional accuracy of this data with respect to the source map was verified by three individuals by visual comparison (manual overlay) of source maps and hard-copy plots. Arcs within one line-width of source mylars were deemed acceptable.
This data set contains geologic units and fault lines as depicted on the source map. There are many additional features on the source map that are not depicted in this coverage, for example, geologic columns, cross-sections and other thematic insets. Quaternary materials are not shown.
When in coverage format, this data set was checked for complete chain-node topology (no dangling arcs, except where appropriate), boundary values appropriate for map projection and map units, and appropriate "fuzzy" tolerances. There are no known arc attribute values outside the appropriate value domains. There are 116 dangling arcs representing the endpoints of fault lines as depicted on source maps.
Are there legal restrictions on access or use of the data?
- Access_Constraints: none
- Use_Constraints:
- Reproduction or redistribution of copyrighted digital data sets or products derived therefrom outside of licensee's organization or entity is expressly forbidden. The only exception is redistribution to consultants working for the licensee, and then only for purposes, related to work for the licensee. Such consultants may not further reproduce or redistribute these data sets. None of these data shall be electronically duplicated on magnetic or optical media for use by others, in whole or in part, without permission of DNR.
Any hardcopies utilizing DNR data sets shall clearly indicate their source. If the licensee has modified the data in any way they are obligated to describe the types of modifications they have performed on the hardcopy map. Licensee specifically agrees not to misrepresent DNR data sets, nor to imply that changes they made were approved by DNR.
217-333-4747 (voice)
isgs@isgs.uiuc.edu
The Illinois Department of Natural Resources (DNR) provides these geographic data "as is." DNR makes no guarantee or warranty concerning the accuracy of information contained in the geographic data. DNR 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 of DNR, no warranty, expressed or implied, is made by DNR 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 DNR 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 DNR.
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The data are intended for use with GIS software. The ISGS uses ESRI ArcGIS software, however, the ESRI shapefile format can be imported into many different GIS software packages.It is expected that customers who order this data have the technical expertise to use GIS software. The ISGS does not provide software support of any kind.
Illinois Natural Resources Geospatial Data Clearinghouse
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