For more current road information, including downloadable GIS data, refer to the Illinois Department of Transportation Technology Transfer Center (IDOT T2 Center) at <http://dot.state.il.us/blr/t2center1.html>.
This metadata document describes the SDE feature dataset as a whole and contains information that applies to all the feature classes. Each feature class has an additional unique metadata file describing its specifics.
Publication dates of the USGS maps used as sources range from 1980 to 1986. Major highways were updated as of 1993. The maximum estimated error in horizontal position based on National Map Accuracy Standards is 167 feet. Experience shows that actual locational error appears to be greater, especially in localized areas. Rough comparison of these data with other easily obtainable, low-cost roads data shows that locational accuracy varies from locale to locale. Other datasets have better accuracy in some areas and worse in others. Overall, the general quality of most low-cost roads data appears to be the same, with local variation.
Attributes include road class, road type, DLG code, route numbers, and data source, among others. The All_Roads feature class is the parent of the other three feature classes and contains all attribute information. The Interstate, State_Routes, and US_Highways feature classes are subsets of All_Roads and contain only route numbers.
The data are stored in geographic coordinates, NAD83.
These data have not been updated since 1993, nor are there current plans to do so. With the exception of major highways, the data have not been updated since 1986. Accordingly, these data are for general reference and cartographic use. This is a legacy dataset made available as a convenience. The data are not suitable for showing all local roads at a large scale for any given area. These data can be considered to be essentially out of date and unmaintained.
These data and most of the accompanying metadata were originally developed and maintained by staff of the Illinois Natural History Survey (INHS), an agency of the Illinois Department of Natural Resources (IDNR), under the auspices of the Illinois Geographic Information System (IGIS) initiative (circa 1986). Maintenance of the metadata was transferred to ISGS circa 1996.
This dataset serves as an important base cartographic element for many types of maps and has been widely distributed and used outside the ISGS. 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.
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.
For more current road information, including downloadable GIS data, refer to the Illinois Department of Transportation Technology Transfer Center (IDOT T2 Center) at <http://dot.state.il.us/blr/t2center1.html>.
This "parent" metadata document was created by amalgamating the coverage metadata.
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.