Soil Thickness of the Illinois River Watershed

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Frequently-anticipated questions:

What does this data set describe?

    Title: Soil Thickness of the Illinois River Watershed
    Soil Thickness within the Illinois River Basin. Derived from USDA created STATSGO. Created by averaging the maximum layer depth for each component of the mapping unit

  1. How should this data set be cited?

    Illinois State Water Survey, September 1999, Soil Thickness of the Illinois River Watershed: Illinois State Water Survey, Champaign, Illinois.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -90.66479701
    East_Bounding_Coordinate: -89.99346251
    North_Bounding_Coordinate: 40.38878863
    South_Bounding_Coordinate: 39.7883752

  3. What does it look like?

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

    Calendar_Date: Mid 1990s
    Currentness_Reference: ground condition

  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 4361 x 3422 x 1, 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: 33.000000
      Standard_Parallel: 45.000000
      Longitude_of_Central_Meridian: -89.500000
      False_Easting: 2999994.000000
      False_Northing: 0.000000

      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 300.000000
      Ordinates (y-coordinates) are specified to the nearest 300.000000
      Planar coordinates are specified in survey feet

      The horizontal datum used is D_Clarke_1866.
      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.

  7. How does the data set describe geographic features?

    Soil Thickness in Inches

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?

    Kingsley Allan and Yiping Guo, ISWS

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

    Illinois State Water Survey
    c/o Kingsley M. Allan
    GIS Manager

    (217)333-0545 (voice)
    (217)333-6540 (FAX)

    Hours_of_Service: Monday to Friday 8 a.m. to 5 p.m.

Why was the data set created?

This dataset was created as the input for watershed model input.

How was the data set created?

  1. Where did the data come from?

    STATSGO (source 1 of 1)
    NRCS, USDA, mid 1990s, State Soil Geographic Data Base (STATSGO):,.

    Online Links:

    Type_of_Source_Media: online
    Source_Scale_Denominator: 250000

  2. What changes have been made?

    (change 1 of 24)
    Download Statsgo vector data.

    (change 2 of 24)
    Download the related tables.

    (change 3 of 24)
    Open up mapunit, comp, and layer files in a texteditor.

    (change 4 of 24)
    Strip off the :i, :c, and :f from the field names.

    (change 5 of 24)
    Delete the second record in the file which is just dashes.

    (change 6 of 24)
    Store the first record which is the field names in one text file and the data in a separate text file. This step is necessary to ensure number fields are not interpreted as character fields.

    (change 7 of 24)
    For each of the mapunit, layer, and comp files, open the data portion file in Excel and save it in Excel format

    (change 8 of 24)
    Open up the header portion file in Excel.

    (change 9 of 24)
    In Excel add a row at the top of the data portion file

    (change 10 of 24)
    Copy and paste the data from the header portion into the top row of the data portion file in Excel.

    (change 11 of 24)
    For the comp file rearrange the column so that seqnum is immediately after muid.

    (change 12 of 24)
    Delete any columns where there is no data for any records.

    (change 13 of 24)
    Save the file in CSV format.

    (change 14 of 24)
    At the system level change the file extensions from .csv to .txt

    (change 15 of 24)
    Open each file in ArcView and Export each to an INFO file.

    (change 16 of 24)
    In Arc/Info Tables redefine muid and seqnum together as a new item muidseq for comp and layer.

    (change 17 of 24)
    In ArcView Sum the layer table on muidseq adding laydeph maxium to the summary table definition.

    (change 18 of 24)
    Join the sum table to comp table on muidseq.

    (change 19 of 24)
    Add numeric dummy field to comp table.

    (change 20 of 24)
    Multiply max_laydeph field by comppct into dummy field.

    (change 21 of 24)
    Sum comp table on muid adding dummy sum to the summary table definition.

    (change 22 of 24)
    Drop count field and export to INFO.

    (change 23 of 24)
    Join summary table to statsgo.pat on muid field.

    (change 24 of 24)
    Convert coverage to GRID

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

  1. How well have the observations been checked?

  2. How accurate are the geographic locations?

  3. How accurate are the heights or depths?

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

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

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?

Access_Constraints: none
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 Illinois State Water Survey (ISWS). Any hardcopies utilizing this data set shall clearly indicate the source. If the user has modified the data in any way they are obligated to describe the types of modifications they have performed on the hardcopy map. The user specifically agrees not to misrepresent ISWS data sets, nor to imply that changes they made were approved by ISWS. Acknowledgement of the ISWS would be appreciated in products derived from these data. These data are not to be used for commercial profit.

  1. Who distributes the data set?[Distributor contact information not provided.]

  2. What's the catalog number I need to order this data set?

  3. What legal disclaimers am I supposed to read?

  4. How can I download or order the data?

Who wrote the metadata?

Last modified: 21-Sep-2000

Metadata author:
Illinois State Water Survey
c/o Kingsley Allan
GIS Manager
2204 Griffith Drive
Champaign, Illinois 61820

217-333-0545 (voice)
217-333-6540 (FAX)

Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)

Metadata extensions used:

Generated by mp version 2.4.38 on Thu Sep 21 17:53:46 2000