Origin of the data:
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.
Updates to the data:
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 (this one) is edition 1.1.
Illinois State Geological Survey, 1998, Glacial Boundaries in Illinois: ISGS GIS Database glcbnd, Illinois State Geological Survey, Champaign, Illinois.Online Links:
- Downloadable Data (Shift-Click to download data file) <URL:http://www.isgs.uiuc.edu/nsdihome/browse/statewide/glcbnd.e00>
- Browse Graphic (GIF) Screen-size image representing the nature of the data. <URL:http://www.isgs.uiuc.edu/nsdihome/browse/statewide/glcbndb.gif>
- Text (.txt) version of this Metadata file. (Shift-Click to download documentation) <URL:http://www.isgs.uiuc.edu/nsdihome/outmeta/glcbnd.txt>
- HTML (.html) version of this Metadata file. (Shift-Click to download documentation) <URL:http://www.isgs.uiuc.edu/nsdihome/outmeta/glcbnd.html>
This is a Vector data set. It contains the following vector data types (SDTS terminology):
The map projection used is Lambert Conformal Conic.
Planar coordinates are encoded using coordinate pair
Abscissae (x-coordinates) are specified to the nearest unknown
Ordinates (y-coordinates) are specified to the nearest unknown
Planar coordinates are specified in feet
The horizontal datum used is NAD27.
The ellipsoid used is CLARKE1866.
The semi-major axis of the ellipsoid used is 6378206.4 meters.
The flattening of the ellipsoid used is 1/294.98.
Attribute items are in typical ARC/INFO feature class format.
Those requiring additional explanation are:
Polygon attributes:
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
GIS processing: Environmental Systems Research Institute, Inc. (ESRI)
ISGS staff
Documentation: R. Krumm, D. Nelson and S. Beaverson
Quality Control: ISGS Staff, D. Nelson, A. Hansel
217-333-4747 (voice)
217-244-0802 (FAX)
isgs@isgs.uiuc.edu
The data are appropriate as a statewide overview of the extent of the major glacial episodes in Illinois. The data are not appropriate as a map base, except in generalized geologic mapping.
J.A. Lineback, Illinois State Geological Survey, 1979, Quaternary Deposits of Illinois: Illinois State Geological Survey, Champaign, Illinois, USA.
Willman, H.B., 1967, Geologic Map of Illinois: Illinois State Geological Survey, Champaign, Illinois, USA.
Hansel, A. and H. Johnson, 1996, Wedron and Mason Groups: Lithostratigraphic Reclassification of Deposits of the Wisconsin Episode, Lake Michigan Lobe Area: Illinois State Geological Survey Bulletin 104, Illinois State Geological Survey, Champaign, Illinois, USA.
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 *path_name_suppressed*/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.
Illinois State Geological Survey, 1984, Quaternary Deposits of Illinois: ISGS GIS Database quat79, Illinois State Geological Survey, Champaign, Illinois.Online Links:
- Data Set Documentation <URL:http://www.isgs.uiuc.edu/nsdihome/outmeta/quat79.html>
Abert, Curtis, 1991, Woodfordian Moraines of Illinois: ISGS GIS Database moraines, Illinois State Geological Survey, Champaign, Illinois.Online Links:
- Data Set Documentation <URL:http://www.isgs.uiuc.edu/nsdihome/outmeta/moraines.html>
Data set information was reviewed by ISGS Staff. Information included is accurate in regard to Hansel and Johnson, ISGS Bull. 104. There are no known polygon attribute values outside the appropriate value domains.
In the ITU data preparation process, glacial boundary lines were adjusted to the boundaries of till members of a Quaternary geology overlay produced during the integration of stack-units and Quaternary geology units. In areas where glacial till was absent (i.e., bedrock, loess, and silt areas) the glacial boundaries were left unchanged. No quantitative assessment of horizontal accuracy is available. These data are intended to show a general statewide overview of the areal extent of glacial episodes. Use at scales greater than 1:500,000 is discouraged.
All known episodic boundaries that can be appropriately mapped at a scale of 1:500,000 are shown. There may exist site-specific studies containing more recent data that are not included here.
Polygon and chain-node topology is present. Typically, ISGS Arc/Info coverages are checked for complete chain-node topology (no dangling arcs, except where appropriate), polygon labels (one per polygon, except for universal polygon), boundary values appropriate for map projection and map units, and appropriate "fuzzy" tolerances.
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 the appropriate custodial division within 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.
These data are not to be used for commercial profit.
These data should not be used at scales greater than 1:500,000.
217-333-4747 (voice)
217-244-0802 (FAX)
isgs@isgs.uiuc.edu
An Arc/Info .e00 (export) file is currently available free of charge at the Illinois Natural Resources Geospatial Data Clearinghouse. Refer to the Citation Information portion of this file for access to downloadable data and metadata, and a visual (GIF image) representation of the data. Shift-click to download the data set and related documentation. (Data and metadata offered separately, please download both files.)
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.
217-333-4747 (voice)
217-244-0802 (FAX)
isgs@isgs.uiuc.edu
Illinois Natural Resources Geospatial Data Clearinghouse
Generated by mp version 2.8.11 on Mon Jan 29 15:19:36 2007