Illinois Statewide 30-Meter Shaded Relief Image

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Frequently-anticipated questions:

What does this data set describe?

Title: Illinois Statewide 30-Meter Shaded Relief Image
Abstract:
This is a shaded relief image of Illinois in ArcSDE raster format. The data are stored in UTM coordinates, using a Transverse Mercator projection with the parameters of UTM Zone 16, NAD27. The data have a 30-meter ground resolution.

The source DEM is a mosaicked model of USGS 30x30 meter DEMs, showing 1:24,000-SCALE quadrangle map boundaries that extend in an irregular buffer outside the state boundary. The source DEM is stored in the ISGS GIS database as GISDB.IL_DEM_30M_RAS.

  1. How should this data set be cited?

    Luman, Donald, Smith, Lisa, and Goldsmith, Chris, 2003, Illinois Statewide 30-Meter Shaded Relief Image: ISGS GIS Database GISDB.IL_DEM_SHADED_RELIEF_30M_RAS, Illinois State Geological Survey, Champaign, IL.

    This is part of the following larger work.

    Luman, Donald, Smith, Lisa, and Goldsmith, Chris, 2003, Illinois Surface Topography: Illinois Map 11, Illinois State Geological Survey, Champaign, Illinois, USA.

    Other_Citation_Details: Scale, 1:500,000. Size, 36 x 54 inches. Color.

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -91.5336
    East_Bounding_Coordinate: -87.2490
    North_Bounding_Coordinate: 42.6108
    South_Bounding_Coordinate: 36.8568

  3. What does it look like?

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

    Calendar_Date: 18-Oct-2001
    Currentness_Reference: Last update with updated USGS DEM data

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

    Geospatial_Data_Presentation_Form: raster digital data

  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 21661 x 12665 x 1, type Pixel

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

      Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:
      UTM_Zone_Number: 16
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.999600
      Longitude_of_Central_Meridian: -87.000000
      Latitude_of_Projection_Origin: 0.000000
      False_Easting: 500000.000000
      False_Northing: 0.000000

      Planar coordinates are encoded using row and column
      Abscissae (x-coordinates) are specified to the nearest 30.000000
      Ordinates (y-coordinates) are specified to the nearest 30.000000
      Planar coordinates are specified in meters

      The horizontal datum used is North American Datum of 1927.
      The ellipsoid used is Clarke 1866.
      The semi-major axis of the ellipsoid used is 6378206.400000.
      The flattening of the ellipsoid used is 1/294.978698.

      Vertical_Coordinate_System_Definition:
      Altitude_System_Definition:

  7. How does the data set describe geographic features?

    Band_1

    ObjectID
    Internal feature number. (Source: ESRI)

    Sequential unique whole numbers that are automatically generated.

    Value

    Count

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?

    Contact_Instructions: Please refer to the distribution information.

Why was the data set created?

These data were developed to produce an ISGS publication entitled Illinois Surface Topography, Illinois Map 11, 2003.

These data are appropriate for use in local and regional elevation analysis. The data are not appropriate as a geodetic, legal or engineering base. The data set can serve as an important base cartographic and analytical element for many types of maps. The data set was not and is not intended as a substitute for surveyed elevations, such as can be determined by a registered Public Land Surveyor.

How was the data set created?

  1. From what previous works were the data drawn?

    (source 1 of 1)
    , USGS DEMs.

    Source_Scale_Denominator: 24000

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

    Date: 2001 (process 1 of 5)
    Imported USGS DEMs to ESRI GRID lattices.

    Date: 2001 (process 2 of 5)
    Standardized all DEMs to UTM 15 or 16 NAD27 with vertical units in feet, and a cell size of 30 meters. Some DEMs that had a datum of NAD83 were projected to NAD27 with cubic resampling. Vertical units were in feet, meters, and decimeters and were converted by simple multiplication and rounded to the nearest whole foot. DEMs with a 10 meter cell size were resized to a 30 meter grid spacing with cubic resampling.

    Person who carried out this activity:

    Date: 2001 (process 3 of 5)
    Due to a limitation in GRID on the number of input grids while mosaicking all the DEMs were first mosaicked into one degree blocks (latitude and longitude) and then into full mosaicks of the UTM 15 and 16 zones in Illinois. Null areas were fillled in by simple averaging of the surrounding cells.

    Person who carried out this activity:

    Date: 2001 (process 4 of 5)
    Final assembly of the statewide DEM was accomplished by reprojecting the UTM 15 side of the state to UTM 16 with cubic resampling and then mosaicking it with the UTM 16 zone.

    The shaded relief image was derived from the DEM.

    Date: 17-Dec-2003 (process 5 of 5)
    The final tif was imported into the ISGS SDE database using LZ77 compression, the GISDB_RASTER configuration keyword, and a raster block size of 80 x 80. Several test loads using ISGS procedure GISDB_0016 were performed to determine the appropriate raster block size. Pyramids were built using bilinear interpolation. Dataset statistics were calculated. Database statistics (analyze function) were calculated. The metadata were updated.

    Person who carried out this activity:

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

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

  1. How well have the observations been checked?

    None.

  2. How accurate are the geographic locations?

    Should be consistant for NMAS specification for a 1:24000 scale map.

  3. How accurate are the heights or depths?

    Half the contour interval of the original USGS topographic survey. A typical interval for Illinois is ten feet although other ranges exist.

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

    None.

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

    None.

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 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.

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

    Illinois State Geological Survey, Geospatial Analysis and Modeling Section
    615 East Peabody Drive
    Champaign, Illinois 61820
    USA

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

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

  5. What hardware or software do I need in order to use the data set?

    The data are intended for use with GIS software. The ISGS uses ESRI ArcGIS software, however, the ESRI shapefile format can be imported into many different GIS software packages. It is expected that customers who order this data have the technical expertise to use GIS software. The ISGS does not provide software support of any kind.

Who wrote the metadata?

Dates:
Last modified: 17-Dec-2003
Metadata author:

Contact_Instructions: Please refer to the distribution information.
Metadata standard:
Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)
Metadata extensions used:

Illinois Natural Resources Geospatial Data Clearinghouse

Generated by mp version 2.8.11 on Wed Jul 18 14:41:51 2007