There are no attribute data associated with the spatial data in this data set. The nominal scale is 1:500,000.
In April 2004 edition 1.1 of the data set was transitioned to storage in an Oracle RDBMS using the ArcSDE geodatabase model. The result (this version) is designated Edition 20040423.
Edition 1.0 of these data were reviewed for internal logical consistency in June, 1998. As a result, tics were replaced, and COVER-ID values were recalculated to be unique. See logical consistency report and process steps for May, 1998 for more details. The updated data set was edition 1.1.
Illinois State Geological Survey, 1994, Driftless Areas in Illinois: ISGS GIS Database GISDB_QTGEO.IL_Driftless_Areas_Py, Illinois State Geological Survey, Champaign, Illinois.
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.
Appropriate applications are regional or statewide studies, preferably at a scale of 1:500,000. These data can be used in conjunction with buried bedrock surface, loess, glacial boundary, and drift thickness information to demonstrate various aspects of the unglaciated portions of Illinois.
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.
Herzog, B.L.. B.J. Stiff, C.A. Chenoweth, K.L, 1994, Buried Bedrock Surface of Illinois: ISGS Illinois Map series 5, Illinois State Geological Survey, Champaign, Illinois.
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.
There are no user-defined attributes included with these data.
All known unglaciated areas as mapped on the source map at a scale of 1:500,000 are included. There may exist site-specific studies containing more recent data that are not included here.
Polygon and chain-node topology was present in the source coverage. The coverage was checked for complete chain-node topology (no dangling arcs, except where appropriate), polygon labels (one per polygon, except for universe polygon), boundary values appropriate for map projection and map units, and appropriate "fuzzy" tolerances. COVER-ID values are unique.
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, firstname.lastname@example.org. 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 09:54:03 2009