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>.
Data were derived from the US Geological Survey 1:100,000 Digital Line Graph files, transportation layer, 1980-1986. Publication dates of the USGS maps used as sources range from 1980 to 1996. (Editor's note - In the metadata for sibling feature classes this range is given as 1980-1986. Correct or typo?) Major highways were updated as of 1996. (Editor's note - In the metadata for sibling feature classes this date is given as 1993. Correct or typo?) The maximum estimated error in horizontal position based on National Map Accuracy Standards is 167 feet. Attributes include up to three interstate route numbers.
The data are stored in geographic coordinates, NAD83.
These data have not been updated since 1996 (1993?), nor are there current plans to do so.
This metadata file was originally written by staff of the INHS. Maintenance of the metadata was transferred to ISGS circa 1996.
Edition 1.1 of this dataset was updated by conversion to the ArcSDE data storage model and metadata update.
Illinois Department of Natural Resources, Illinois Natural History Survey, and Illinois State Geological Survey, 1996, Interstates and Toll Roads in Illinois: ISGS GIS Database GISDB.IL_INFRA_ROADS_Interstates_Ln, Illinois State Geological Survey, Champaign, Illinois.Online Links:
This is a Vector data set. It contains the following vector data types (SDTS terminology):
Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.000001. Longitudes are given to the nearest 0.000001. Latitude and longitude values are specified in Decimal degrees.
The horizontal datum used is North American Datum of 1983.
The ellipsoid used is Geodetic Reference System 80.
The semi-major axis of the ellipsoid used is 6378137.000000.
The flattening of the ellipsoid used is 1/298.257222.
INT_1, INT_2, and INT_3 The value is equal to the designated route number of the interstate. Three fields are used to account for areas where several interstates overlap. A line may have up to three numerical designations. Any route having a value for INT_2 or INT_3 should also have a value for INT_1. All lines have at least one route number, with a single exception: The Elgin-O'Hare Expressway had not been officially numbered when the dataset was last updated. Valid values are 24, 39, 55, 57, 64, 70, 72, 74, 80, 88, 90, 94, 155, 172, 180, 190, 255, 270, 290, 294, 355, and 474. Values are from DLG files, 1980-86, USGS and IDOT county base map series.
US - The value is equal to the US highway route where the arc represents both a portion of the interstate system and the US highway system. If one or more US highways overlap the interstate, the value includes all designated route numbers separated by a zero. Valid values are 6, 36, 40, 50, and 51.
STATE - The value is equal to the Illinois highway route where the arc represents both a portion of the interstate system and the Illinois highway system. When the dataset was last updated, no portions of the interstate system overlapped with the Illinois highway system.
Coverage construction: ISGS and INHS staff Latest feature updates: ISGS staff Documentation: ISGS and INHS staff Quality Control: ISGS and INHS staff
In a natural resources context, interstates and toll roads are primarily used as a cartographic element on maps for spatial reference. They are also used for analyses that require, for example, a buffer area between roads and natural features. These data are appropriate for use in regional thematic analysis. They are not appropriate for local analysis or as a geodetic or engineering base.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.
Survey, US Geological , 1980-1991, US Geological Survey 1:100,000 Digital Line Graph files, transportation layer.
Survey, US Geological , varies, US Geological Survey 1:24,000 topographic quadrangles.
Field names including the pound-sign character were renamed to eliminate that character (not allowed by Oracle). The INTERST# field was dropped as it was redundant with INT_1, INT_2, and INT_3.
Spatial index grid size was set at 0.9 degrees.
Metadata was updated.
Person who carried out this activity:
, ISGS Terms of Use.Online Links:
, University of Illinois Web Privacy Notice.Online Links:
, University Copyright Policy (stated in the General Rules Concerning University Organization and Procedure, Article III, Section 4).Online Links:
, Policy on Appropriate Use of Computers and Network Systems at the University of Illinois at Urbana-Champaign.Online Links:
No report.
It is assumed accuracy is equal to that of 1:100,000 analog source maps based on USGS National Map Accuracy Standards. Some updates were taken from USGS 7.5' topographic quadrangles. These updates are within one line-width of the corresponding line on the source map. No accuracy statement was provided with the source maps.
No statement of completeness was provided with the original USGS DLG data. Visual inspection and use suggests this was comprehensive in 1996. All interstates and toll roads contained in the source USGS 1:100,000 DLG files are included. Some updates were made in 1993 and 1996. Any new interstate highways since 1993 are not included.
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>.
No report.
Are there legal restrictions on access or use of the data?
- Access_Constraints:
- ISGS information must be obtained directly from the ISGS or from an authorized distributor. Be aware that ISGS information obtained from an unauthorized third party may have been altered subsequent to original distribution, or may no longer be current.
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.
- Use_Constraints:
- ISGS information is the property of and copyrighted by the Board of Trustees of the University of Illinois with all rights reserved. University copyright policy is stated in the General Rules Concerning University Organization and Procedure, Article III, Section 4. A link is 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.
217-333-4747 (voice)
isgs@isgs.illinois.edu
Refer to the Legal Notices of Terms and Conditions of the University of Illinois Web Privacy Policy (there is a link in the Cross References section) for policy statements regarding the following: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.
The data are intended for use with GIS software. The ISGS uses ESRI ArcGIS software, however, ESRI formats can be imported into many different GIS software packages. It is expected that customers who obtain these data have the technical expertise to use GIS software. The ISGS does not provide software support of any kind.
Illinois Natural Resources Geospatial Data Clearinghouse
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