Illinois Historical Aerial Photographs: Schematic County Indexes v.2

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Frequently-anticipated questions:

What does this data set describe?

Title:
Illinois Historical Aerial Photographs: Schematic County Indexes v.2
Abstract:
This data set consists of schematic or line drawn indexes of Illinois historical black and white aerial photographs, acquired during the late 1930s and early 1940s. The original paper indexes have been scanned and saved as TIFF format images. The images available online are MrSID files, in which the original TIFF files were compressed at a target ratio of 15:1 or 6:1 (see process steps "IMAGE COMPRESSION" below). The scale of the data varies from county to county.

These data have not been geometrically corrected.

  1. How should this data set be cited?

    Illinois State Geological Survey, Unpublished Material, Illinois Historical Aerial Photographs: Schematic County Indexes v.2.

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -91.675280
    East_Bounding_Coordinate: -87.483350
    North_Bounding_Coordinate: 42.564692
    South_Bounding_Coordinate: 36.911398

  3. What does it look like?

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

    Beginning_Date: 1936
    Ending_Date: 1941
    Currentness_Reference: publication date

  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, type Pixel

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

      This local coordinate system was used: These data are not geometrically corrected.

      Not Applicable

      The horizontal datum used is none.
      The ellipsoid used is none.
      The semi-major axis of the ellipsoid used is none.
      The flattening of the ellipsoid used is 1/none.

  7. How does the data set describe geographic features?

    Entity_and_Attribute_Overview: Not Applicable
    Entity_and_Attribute_Detail_Citation: Not Applicable

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?

These data are provided as supplemental imagery to aid in understanding the organization of the historical aerial photograph collections.

How was the data set created?

  1. From what previous works were the data drawn?

    Not Applicable (source 1 of 1)
    unknown, Unpublished Material, Illinois Historical Aerial Photograph Schematic County Indexes: UIUC Map and Geography Library, Champaign, Illinois.

    Type_of_Source_Media: paper
    Source_Scale_Denominator: varies
    Source_Contribution: Not Applicable

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

    Date: 2001 (process 1 of 4)
    SCANNING METHODOLOGY: Original copies of the county indexes are located at the University of Illinois Map and Geography Library. Special permission was granted by the Library for the county index sheets to be scanned at an offsite location. The indexes were scanned on a large format Eagle 4080 scanner located at the Illinois State Geological Survey. The schematic (line drawn) indexes were scanned at 300 dpi as a grayscale image (2001-2004).

    In December 2004 Historic Information Gatherers, Inc.(HIG), Hopkins, Minnesota, scanned all of the remaining county index sheets (photo mosaic and line indexes that hadn't already been scanned by the ISGS) available at the UIUC Map and Geography Library (~1700 sheets). In Spring 2005 HIG provided the ISGS with digital images of the photo and line indexes. The indexes were scanned on a large format Vidar Titan Atlas P93 scanner temporarily located at the UIUC Map and Geography Library. The schematic (line drawn) indexes were scanned at 400 dpi as a bitmap image (2004).

    Date: 2003 (process 2 of 4)
    IMAGE MANIPULATION: The schematic (line drawn) indexes at the UIUC Map and Geography Library are individually stored in clear archival plastic sleeves within map storage cabinets. Due to space issues many of the schematic indexes have been separated along old fold lines into 2 sheets before they were sealed in the archival plastic sleeves. This allows the sheets to be stored flat in the map storage cabinets without any folds. After the sheets have been scanned they are pieced back together using Adobe Photoshop ver 7.0. Once the schematic index is one sheet again it is ready for compression. The Winnebago County schematic index was changed to a grayscale image and downsampled to 150 dpi using Adobe Photoshop ver 7.0.

    Date: 2003 (process 3 of 4)
    IMAGE COMPRESSION (2003-2004): This methodology was employed for 31 counties with schematic (line drawn) indexes that were scanned at ISGS. These counties include Adams, Clark, Clinton, Cumberland, DuPage, Fulton, Greene, Hancock, Jersey, Kane, Kankakee, Kendall, Lake, Madison, Marshall, Mason, McHenry, Monroe, Morgan, Peoria, Pike, Pulaski, Putnam, St. Clair, Sangamon, Schuyler, Scott, Stark, Tazewell, Washington and Woodford Counties.

    The original scanned files are archived in TIFF format on CD-ROM at the Illinois State Geological Survey.

    The files available for download have been compressed using LizardTech's GeoExpress (Solaris platform) MrSID version 1.3.1 software at a compression ratio of 15:1.

    Date: 2006 (process 4 of 4)
    IMAGE COMPRESSION (2006): This methodology was employed for 1 county (Winnebago County) with a schematic (line drawn) index that was scanned at the UIUC Map and Geography Library by HIG.

    A copy of the original scanned file is archived in TIFF format on CD-ROM at the Illinois State Geological Survey.

    The file available for download has been compressed using LizardTech's GeoExpress (Solaris platform) MrSID Version 5.0.6.1088.Bob_1055_br software at a compression ratio of 6:1.

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

    Illinois State Geological Survey, Unpublished Material, Illinois Historical Aerial Photographs: 1936 to 1941: Illinois State Geological Survey, Champaign, Illinois.

    Online Links:

    Illinois State Geological Survey, Unpublished Material, Illinois Historical Aerial Photographs: County Index Data Layer: Illinois State Geological Survey, Champaign, Illinois.

    Online Links:

    Illinois State Geological Survey, Unpublished Material, Illinois Historical Aerial Photographs: Photo Mosaic County Indexes: Illinois State Geological Survey, Champaign, Illinois.

    Online Links:

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?

    These data have not been geometrically corrected.

  3. How accurate are the heights or depths?

    These data have not been orthorectified.

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

    Not Applicable

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

    Not Applicable

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 there from outside of licensee 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 the Illinois Department of Natural Resources (IDNR).

Any hardcopies utilizing IDNR 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 IDNR data sets, nor to imply that changes they made were approved by IDNR.

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?

    A TIFF format file is currently available free of charge at the Illinois Natural Resources Geospatial Data Clearinghouse. Refer to the Identification_Information portion of this file for access to downloadable data and metadata.

  3. What legal disclaimers am I supposed to read?

    The Illinois Department of Natural Resources provides these geographic data "as is." IDNR makes no guarantee or warranty concerning the accuracy of information contained in the geographic data. IDNR 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 IDNR, no warranty, expressed or implied, is made by IDNR 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 IDNR 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 IDNR.

  4. How can I download or order the data?

Who wrote the metadata?

Dates:
Last modified: 11-Aug-2006
Last Reviewed: 11-Aug-2006
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