Interstates and Toll Roads in Illinois

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Frequently-anticipated questions:


What does this data set describe?

Title: Interstates and Toll Roads in Illinois
Abstract:
This data set contains interstates and toll roads for Illinois. This is a subset of the roads data set stored by county. Note that the functional classification of roadways is the jurisdiction of the Illinois Department of Transportation and is subject to change. Data are 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. Major highways were updated as of 1996. The maximum estimated error in horizontal position based on National Map Accuracy Standards is 167 feet. Attributes include up to three interstate route numbers.

Supplemental_Information:
Updates to this coverage from edition 1.0 include the additions of attribute items US# and STATE#, the addition of I-72 from west of Springfield to the state line (Quincy), and the Elgin-O'Hare Expressway.

  1. How should this data set be cited?

    Illinois State Geological Survey, 1996 - not published, Interstates and Toll Roads in Illinois: IDNR GIS Database intstate, Illinois State Geological Survey, Champaign, Illinois.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -91.50365772
    East_Bounding_Coordinate: -87.41759666
    North_Bounding_Coordinate: 42.49181859
    South_Bounding_Coordinate: 36.98415011

  3. What does it look like?

  4. Does the data set describe conditions during a particular time period?

    Calendar_Date: 1996
    Currentness_Reference: publication date

  5. What is the general form of this data set?

    Geospatial_Data_Presentation_Form: map

  6. How does the data set represent geographic features?

    1. How are geographic features stored in the data set?

      This is a Vector data set. It contains the following vector data types (SDTS terminology):

      • String (381)

    2. What coordinate system is used to represent geographic features?

      The map projection used is Lambert Conformal Conic.

      Projection parameters:
      Standard_Parallel: 33
      Standard_Parallel: 45
      Longitude_of_Central_Meridian: -89.5
      Latitude_of_Projection_Origin: 33
      False_Easting: 914400.00000 meters
      False_Northing: 0.00000

      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest not determined
      Ordinates (y-coordinates) are specified to the nearest not determined
      Planar coordinates are specified in feet

      The horizontal datum used is NAD27.
      The ellipsoid used is Clarke 1866.
      The semi-major axis of the ellipsoid used is 6378206.4 meters.
      The flattening of the ellipsoid used is 1/294.98.

  7. How does the data set describe geographic features?

    Entity_and_Attribute_Overview:
    Attribute items are in typical ARC/INFO feature class format. Those requiring additional explanations are:

    Arc Attributes:

    INTERST# - The value is equal to the designated route number of the interstate. Where several interstates overlap, the value includes all designated route numbers separated by a zero. For example, 70057 indicates that the arc represents a portion of the interstate that is designated both as I-57 and I-70. There is a single exception: The Elgin-O'Hare Expressway has not been officially numbered. 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.

    INTERST# - Redefined to INT#1, INT#2, INT#3 INT#1, INT#2, and INT#3 - Interstate route numbers Route numbers are contained in a single item which is subsequently redefined to deal with coincident routes (routes carrying more than one highway route number). Any route having a value for route 2 or 3 should also have a value for route 1. 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. Currently, no portions of the interstate system overlap with the Illinois highway system.

    Entity_and_Attribute_Detail_Citation: none


Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)

  2. Who also contributed to the data set?

     Coverage construction: ISGS and INHS staff
     Latest updates: B. Stiff, P. Weibel
     Documentation: D. Nelson, P. Weibel, and S. Beaverson
     Quality Control: ISGS and INHS staff
    

  3. To whom should users address questions about the data?

    Illinois State Geological Survey
    Information Office
    615 East Peabody Drive
    Champaign, Illinois 61820
    USA

    217-333-4747 (voice)
    217-244-0802 (FAX)
    isgs@isgs.uiuc.edu

    Hours_of_Service: 8:00 a.m. - 4:30 p.m., Monday-Friday, U.S. Central Time


Why was the data set created?

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 local and regional thematic analysis. They are not appropriate as a geodetic or engineering base.


How was the data set created?

  1. From what previous works were the data drawn?

    none (source 1 of 2)
    Survey, US Geological , 1980-1991, US Geological Survey 1:100,000 Digital Line Graph files, transportation layer.

    Type_of_Source_Media: digital file
    Source_Scale_Denominator: 100000
    Source_Contribution:
    Location of interstate roads as contained in the USGS 1:100,000 DLG files

    none (source 2 of 2)
    Survey, US Geological , varies, US Geological Survey 1:24,000 topographic quadrangles.

    Type_of_Source_Media: paper
    Source_Scale_Denominator: 24000
    Source_Contribution:
    Update information for I-72 from west of Springfield to the state line (Quincy), and the Elgin-O'Hare Expressway

  2. How were the data generated, processed, and modified?

    Date: 1980 (process 1 of 3)
    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 1986.

    Date: 1993 (process 2 of 3)
    Major highways were updated as of 1993 by the Illinois Natural History Survey.

    Date: 1996 (process 3 of 3)
    This coverage was clipped on January 1, 1996 to exclude arcs extending beyond the Illinois state boundary, using the coverage re-state1. Additional updates occurred on June 10, 1996 by the Illinois State Geological Survey, again using the USGS 1:100,000 DLGs. Arcs were selected from the DLGs and appended to this coverage and route values were updated in the items as appropriately needed. Updates were also made from USGS 1:24,000 topographic quadrangles.

  3. What similar or related data should the user be aware of?

    Illinois Department of Natural Resources, 1994, Illinois State Roads: IDNR GIS Database stroutes, Illinois Department of Natural Resources, Champaign, Illinois.

    Online Links:

    Illinois Department of Natural Resources, 1994, U. S. Highways in Illinois: IDNR GIS Database ushways, Illinois Department of Natural Resources, Champaign, Illinois.

    Online Links:


How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?

    not available

  2. How accurate are the geographic locations?

    In general, 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 map.

  3. How accurate are the heights or depths?

  4. Where are the gaps in the data? What is missing?

    No statement of completeness was provided with the original USGS DLG data. Visual inspection and use suggests that coverage is comprehensive but reflective of the date of source map publication date. This date varies across the state. All interstates and toll roads contained in USGS 1:100,000 DLG files are included.

  5. How consistent are the relationships among the observations, including topology?

    Chain-node topology present. Data set is topologically structured linear data with nodes at all intersections. Pseudo nodes (nodes between arcs with common attribute values across all non-system attribute fields) may exist on some arcs.


How can someone get a copy of the data set?

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 licensees' 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.

  1. Who distributes the data set? (Distributor 1 of 1)

    Illinois State Geological Survey
    Information Office
    615 East Peabody Drive
    Champaign, Illinois 61820
    USA

    217-333-4747 (voice)
    217-244-0802 (FAX)
    isgs@isgs.uiuc.edu

    Hours_of_Service: 8:00 a.m. - 4:30 p.m., Monday-Friday, U.S. Central Time
  2. What's the catalog number I need to order this data set?

    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.

  3. What legal disclaimers am I supposed to read?

    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.

  4. How can I download or order the data?


Who wrote the metadata?

Dates:
Last modified: 31-Jul-1998
Last Reviewed: 31-Jul-1998
To be reviewed: Aug-2000
Metadata author:
Illinois State Geological Survey
Information Office
615 East Peabody Drive
Champaign, Illinois 61820
USA

217-333-4747 (voice)
217-244-0802 (FAX)
isgs@isgs.uiuc.edu

Hours_of_Service: 8:00 a.m. - 4:30 p.m., Monday-Friday, U.S. Central Time
Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)


Illinois Natural Resources Geospatial Data Clearinghouse

Generated by mp version 2.8.11 on Mon Jan 29 15:19:37 2007