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.
This layer originated with the Integrated Terrain Unit (ITU) digital data set prepared for the ISGS by Environmental Systems Research Institute, Inc. (ESRI) of Redlands, California in 1984.
The ITU manuscript synthesizes and organizes natural resource information for the state. Data included are natural divisions, bedrock geology, Quaternary geology, STACK units, glacial boundaries, soul associations, SCS land resource areas, ecoregions, and potential natural vegetation. The mapping resolution was generally 640 acres. Waterbodies were mapped to a minimum size of 320 acres. Data were integrated in the following order: Quaternary geology, stack units, glacial boundaries, bedrock geology, soil associations, natural divisions, potential natural vegetation, SCS land resource areas, and finally ecoregions.
Recent updates to the data:
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 May, 1998. As a result, tics were replaced, COVER-ID values were recalculated to be unique, and major revisions were made to polygon boundaries and attributes. See logical consistency report and process steps for May, 1998 for more details. The updated data set was edition 1.1.
Any access to these data, Web sites, computer systems, electronic services, and electronic networks is governed by University and campus policies, in particular, but not limited to, the Policy on Appropriate Use of Computers and Network Systems at the University of Illinois at Urbana-Champaign, the ISGS Terms of Use document available at the ISGS Web site, and the University of Illinois Web Privacy Notice.
Links to these are 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, isgs@isgs.illinois.edu. License fees and a license agreement may be required, depending on the proposed usage.
Any use of these data is governed by University and campus policies, in particular, but not limited to, the Policy on Appropriate Use of Computers and Network Systems at the University of Illinois at Urbana-Champaign, the ISGS Terms of Use document available at the ISGS Web site, and the University of Illinois Web Privacy Notice. Links to these are provided in the Cross References section.
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.
Some changes were made, as follows:
The existing set of tics was replaced by the set of tics from the coverage RE-STATE1. These were derived from 7.5 minute quadrangle corners (data set QUAD75) and give a good distribution of tics immediately outside the state boundary. COVER-ID values were recalculated to be unique. The existing state boundary line was replaced with the boundary from coverage state for general update purposes and to remove the portion of the state boundary that lies within the Lake Michigan area.
Most importantly, the spatial extent and attribute values of several polygons were changed to reflect the lithostratigraphic reclassification of deposits as described in ISGS Bulletin 104 (Hansel and Johnson, 1996). Specifically, polygons coded as Late, Middle or Early Woodfordian were amalgamated into a single polygon coded as Wisconsinan. Polygons coded as Altonian or Illinoian (undifferentiated) were amalgamated into a single polygon coded as Illinoian. Polygons coded as Kansan (undifferentiated) were recoded to Pre-Illinoian. Polygons coded as Not Glaciated were unchanged.
The features were imported into the ISGS SDE enterprise database following steps outlined in ISGS procedure GISDB_0009.
Metadata updated.
GLC-BND - Identifies the glacial episode (using the boundaries and diachronic terminology of Hansel and Johnson, 1996) 2 - Wisconsin 5 - Illinois 6 - Pre-Illinois 9 - Not glaciated
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
By obtaining these data you agree to the provisions of the University of Illinois Web Privacy Policy, regardless of the manner in which the information was obtained.
Illinois Natural Resources Geospatial Data Clearinghouse
Generated by mp version 2.8.25 on Thu Apr 02 09:54:04 2009