With the exception of GISDB_HYDRO.IL_Shallow_Coarse_Materials_Py, the attribute information is limited to a simple binary code indicating the area is or is not an aquifer. The shallow coarse materials feature class was derived from the statewide stack-unit map and contains stack-unit designations.
The data are in the Geographic Coordinate System, decimal degrees, NAD83.
Most of the feature classes have a scale of 1:500,000. GISDB_HYDRO.IL_Shallow_Coarse_Materials_Py has a scale of 1:250,000.
Please refer to the metadata for the individual feature classes.
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.
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, 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.
The various coverage feature classes were imported using ArcCatalog 8.3. Some unnecessary data fields were dropped. Refer to the feature class-specific metadata for details.
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 created.
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