These data are appropriate for use in regional thematic analysis. The data are not appropriate as a geodetic, legal or engineering base. The datasets were not and are not intended as a substitute for surveyed locations, such as can be determined by a registered Public Land Surveyor. Although useful in a GIS, the data have no legal basis in the definition of boundaries or property lines.
In April 2004 the source coverage was transitioned to storage in an Oracle RDBMS using the ArcSDE geodatabase model. The result (this version) is designated edition 20040408. Prior to this time the feature classe was stored as a coverage in the ISGS GISDB archive.
Edition 2.0 differed from edition 1.0 in that some sinkhole polygons in northwestern Illinois were deleted after field examination suggested that the depressions may have an origination other than by sinkhole formation. In addition, additional sinkhole area polygons were added in southern, southwestern, and western Illinois.
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.
Source map underwent ISGS peer review. Line accuracy was checked by overlay of digital print-outs to original compilation maps. Lines within one line-width of source maps were deemed acceptable. Attribute accuracy was verified against source maps.
Prior to import, the spatial reference of the data set was changed to Geographic, decimal degrees, NAD83 in double precision.
Also at this time, this metadata file was updated.
KARST - a value of "y" indicates polygon represents a karst area
SQMILES - area of the polygon in square miles
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.
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.