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.
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.
Person who carried out this activity:
, University of Illinois Web Privacy Notice.
, University Copyright Policy (stated in the General Rules Concerning University Organization and Procedure, Article III, Section 4).
, Policy on Appropriate Use of Computers and Network Systems at the University of Illinois at Urbana-Champaign.
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?
- ISGS information must be obtained directly from the ISGS or from an authorized distributor. Be aware that ISGS information obtained from an unauthorized third party may have been altered subsequent to original distribution, or may no longer be current.
Links to these are provided in the Cross References section.
- ISGS information is the property of and copyrighted by the Board of Trustees of the University of Illinois with all rights reserved. University copyright policy is stated in the General Rules Concerning University Organization and Procedure, Article III, Section 4. A link is provided in the Cross References section.
Individuals or entities may make fair use of copyrighted ISGS material, such as reproducing a single figure or table, or using a brief text quotation, without obtaining formal permission, but in all cases the Illinois State Geological Survey must be credited as the source of the material. To reproduce ISGS information beyond the fair use standard, permission must be obtained from the ISGS Information Office, 615 East Peabody Drive, Champaign, Illinois 61820, 217-333-4747, email@example.com. License fees and a license agreement may be required, depending on the proposed usage.
Map information is to be used at a scientifically and cartographically appropriate scale, that is, at a scale no greater than indicated on the map or as described in the documentation of the map or map data. Map information is not appropriate for, and is not to be used as, a geodetic, legal, or engineering base. Map information has no legal basis in the definition of boundaries or property lines and is not intended as a substitute for surveyed locations such as can be determined by a registered Public Land Surveyor.
The data do not replace the need for detailed site-specific studies.
Disclaimer of Liability Disclaimer of Warranties and Accuracy of Data Disclaimer of Endorsement Disclaimer for External Links Disclaimer of Duty to Continue Provision of Data Security Choice of Law
The data are intended for use with GIS software. The ISGS uses ESRI ArcGIS software, however, ESRI formats can be imported into many different GIS software packages. It is expected that customers who obtain these data have the technical expertise to use GIS software. The ISGS does not provide software support of any kind.
Illinois Natural Resources Geospatial Data ClearinghouseGenerated by mp version 2.8.25 on Thu Apr 02 09:54:04 2009