Critical Trends Assessment Land Cover Database of Illinois, 1991-1995

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Frequently-anticipated questions:


What does this data set describe?

Title:
Critical Trends Assessment Land Cover Database of Illinois, 1991-1995
Abstract:
County by county land cover grid data for Illinois derived from Thematic Mapper (TM) Satellite data from the Landsat 4 sensor. Dates of the imagery used range from April, 1991 to May, 1995. 21 Scenes were used, two dates for each of ten scene areas needed to cover the state (Path/Row 24/31, 24/32, 24/33, 23/31, 23/32, 23/33, 23/34, 22/32, 22/33, 22/34) with an additional single scene needed to fill a small area along the northern border (24/30). Raw data were obtained in Space Oblique Mercator projection for 14 scenes, 7 scenes were delivered in UTM zone 16. Georeferenced data were modified using vector field segmentation with a threshold of 70 prior to being separated into urban and non-urban sets which were then clustered using PCI Image Processing software's ISOCLUS (ISODATA) algorithm. In addition, areas falling under a modified boundary of municipal areas determined by the 1992 TIGER/Line files was used to identify built up areas in the non-urban landscape. The urban classes for these areas were imposed upon the non-urban classified landscape. In general 250 spectral clusters were identified in the non-urban areas with 100 to 150 clusters being identified for the urban areas. A Maximum Likely Classification was run using the signatures generated by ISOCLUS to create the theme channel used for coding. Ancillary data included the Illinois Wetlands Inventory, NRCS (ASCS) county crop compliance data, 1988 CIR NAPP photography (20% sample), 1988 BW NAPP (100%) sample, DNR digital vector roads, streams, and railroads. Nineteen Land cover classes were identified.

Supplemental_Information:
The path to these data sets is /gisdb/county/<county_name>/landcov where <county_name> should be replaced with the name of the county of interest. Longer county names have been truncated to eight characters.

  1. How should this data set be cited?

    Dr. Donald Luman, Mark Joselyn, Liane Suloway, Illinoi, 199603, Critical Trends Assessment Land Cover Database of Illinois, 1991-1995: IDNR GIS Database /gisdb/county/<county_name>/landcov, Illinois Department of Natural Resources, Champaign, Illinois.

    This is part of the following larger work.

    Illinois Natural History Survey, Illinois State Geological Survey, Illino, 199603, Critical Trends Assessment Land Cover Database of Illinois, 1991-1995: Illinois Department of Natural Resources, Champaign, Illinois.

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -91.7
    East_Bounding_Coordinate: -87.5
    North_Bounding_Coordinate: 42.76
    South_Bounding_Coordinate: 36.9

  3. What does it look like?

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

    Beginning_Date: 17-Apr-1991
    Ending_Date: 30-May-1995
    Currentness_Reference: Acquisition date of raw imagery by satellite

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

    Geospatial_Data_Presentation_Form: remote-sensing image

  6. How does the data set represent geographic features?

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

      This is a Raster data set. It contains the following raster data types:

      • Dimensions varies for each county x varies for each county, type Grid Cell

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

      The map projection used is Lambert Conformal Conic.

      Projection parameters:
      Standard_Parallel: 33 0 0.000
      Standard_Parallel: 45 0 0.000
      Longitude_of_Central_Meridian: -89 30 0.000
      Latitude_of_Projection_Origin: 33 0 0.000
      False_Easting: 914400.00000 meters
      False_Northing: 0.00000

      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest unknown
      Ordinates (y-coordinates) are specified to the nearest unknown
      Planar coordinates are specified in feet

      The horizontal datum used is NAD27.
      The ellipsoid used is CLARKE1866.
      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:
    LAND COVER CLASSES: NOTE: Class values stored in item VALUE for each Arc/Info Grid

    Urban and Built-Up Land 1 - High Density (all or most of the surface cover is comprised of ' impervious material) 2 - Medium-High Density (transitional between Medium and High Density; ' located in Cook County only) 3 - Medium Density (a significant proportion of the surface cover ' is comprised of impervious material) 4 - Low Density (small amount of surface area comprised of ' impervious material mixed with other land cover such as ' Grassland, Wooded Land, etc.)

    Transportation [ONLY PRESENT IN land2utm] 5 - Major Roadways (Major Highways updated 1992) 6 - Active Railroads (1991) 7 - Abandoned Railroads (1991)

    Crop Land 8 - Row Crop (corn, soybeans, and other tilled crops) 9 - Small Grains (wheat, oats, etc.) 10 - Orchards/Nurseries

    Grassland 11 - Urban Grassland (parks, residential lawns, golf courses, ' cemeteries, and other open space) 12 - Rural Grassland (pastureland, grassland, waterways, ' buffer strips, CRP land, etc.)

    Wooded and Forested Land 13 - Deciduous: undifferentiated broadleaf deciduous, closed canopy 14 - Deciduous: undifferentiated broadleaf deciduous, open canopy 15 - Coniferous: undifferentiated

    16 - Open Water 17 - Perennial Streams [ONLY PRESENT IN land2utm]

    Wetland 18 - Shallow Marsh/Wet Meadow 19 - Deep Marsh 20 - Forested Wetlands 21 - Swamp 22 - Shallow Water Wetlands

    23 - Barren Land (e.g., quarries, sandy beaches, ' exposed soil surfaces, etc.)

    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?

  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?

This database was completed as an integral part of the Critical Trends Assessment Project. It is intended to serve as a base line for assessment and management of biologic natural resources in Illinois. It is a good medium scale land cover map of the entire state.


How was the data set created?

  1. From what previous works were the data drawn?

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

    Date: unknown (process 1 of 1)
    see abstract

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

    Illinois Natural History Survey, 199603, Colormap file to reproduce the colors of the published (hardcopy) map.: IGIS GIS Database /gisdb/ancillary/landcov.clr.


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

  1. How well have the observations been checked?

    No accuracy assessment of the classification has been performed.

  2. How accurate are the geographic locations?

    Agrees with the 1:100,000 vector layers very well.

  3. How accurate are the heights or depths?

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

    All of Illinois is covered. A local filter was run after classification. The threshold used ranged from 2 pixels to 6 pixels.

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

    not available


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 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 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.

Identification of Illinois Department of Natural Resources, Critical Trends Assessment Project as the source is mandatory.

  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?

  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: 07-Mar-1997
Last Reviewed: 07-Mar-1997
To be reviewed: 01-Apr-1998
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

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