Structural Features - 1995

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Frequently-anticipated questions:

What does this data set describe?

Title: Structural Features - 1995
Abstract:
This feature dataset is a representation of Plate 1 from ISGS Bulletin 100 (1993) by W. John Nelson. Features depicted are limited to well documented, significant faults, faulted flexures and grabens in Illinois. Names of the features and the associated directions of faulting are included. (Note: Plate 1 is dated 1993, while the full publication is dated 1995.)
Supplemental_Information:
These data are generally considered to supersed structural feature data compiled in ISGS Circular 519, Structural Features in Illinois - A Compendium (Treworgy,1982). The 1982 data have been preserved for historical reasons and because they include many features that are no longer considered valid, and thus are not included in ISGS Bulletin 100. Data from Circ. 519 are also available in digital format. Generally, those interested in currently recognized and named structural features should use the data associated with Bull. 100. Those interested in other possible additional structures or historical structure names may want to use the data for Circular 519. Those unsure of which data set to use should consult both Bulletin 100 and Circular 519 in order to make an informed decision.

Recent updates to the data:

In March 2004 edition 1.0 of the data set was transitioned to storage in an Oracle RDBMS using the ArcSDE geodatabase model. The result (this version) is designated Edition 20040331.

  1. How should this data set be cited?

    Illinois State Geological Survey, 1995, Structural Features - 1995: ISGS GIS Database GISDB_BEDGEO.IL_Structural_Features_1995, Illinois State Geological Survey, Champaign, Illinois.

    Online Links:

    This is part of the following larger work.

    Nelson, W. John , 1995, Structural Features in Illinois: ISGS Bulletin 100, Illinois State Geological Survey, Champaign, Illinois, USA.

    Other_Citation_Details: Plate 1, scale 1:500,000

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -91.50537511
    East_Bounding_Coordinate: -87.4319598
    North_Bounding_Coordinate: 42.4976416
    South_Bounding_Coordinate: 37.07536813

  3. What does it look like?

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

    Calendar_Date: 1993
    Currentness_Reference: publication date of Plate 1 of Bull. 100

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

    Geospatial_Data_Presentation_Form: vector digital data

  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 (137)
      • String (407)
      • Entity point (52)
      • G-polygon (89)

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

      Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.000001. Longitudes are given to the nearest 0.000001. Latitude and longitude values are specified in Decimal degrees.

      The horizontal datum used is North American Datum of 1983.
      The ellipsoid used is Geodetic Reference System 80.
      The semi-major axis of the ellipsoid used is 6378137.000000.
      The flattening of the ellipsoid used is 1/298.257222.

      Vertical_Coordinate_System_Definition:
      Altitude_System_Definition:

  7. How does the data set describe geographic features?

    GISDB_BEDGEO.IL_Struct_Feat_Clines_1995_Ln

    GISDB_BEDGEO.IL_Struct_Feat_Faults_1995_Ln

    GISDB_BEDGEO.IL_Structural_Features_1995_Pt

    GISDB_BEDGEO.IL_Structural_Features_1995_Py

    Entity_and_Attribute_Overview:
    See the metadata of the individual feature classes for specific attribute information.

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 section.

Why was the data set created?

Applications are regional or statewide studies, preferably at a scale of 1:500,000.

The data are not appropriate as a geodetic, legal or engineering base. The data set was not and is not intended as a substitute for surveyed locations, such as can be determined by a registered Public Land Surveyor. Although useful in a GIS as a reference base layer for maps, the data set has no legal basis in the definition of boundaries or property lines.

How was the data set created?

  1. From what previous works were the data drawn?

    none (source 1 of 4)
    Nelson, W. John, 1993, Structural Features in Illinois, Plate 1: ISGS Bulletin 100, Illinois State Geological Survey, Champaign, Illinois.

    Type_of_Source_Media: paper
    Source_Scale_Denominator: 500000
    Source_Contribution: line feature attributes

    none (source 2 of 4)
    Nelson, W. John, 1993, Original Mylar Separates for Plate 1 of Structural Features in Illinois: ISGS Bulletin 100, Illinois State Geological Survey, Champaign, Illinois.

    Type_of_Source_Media: mylar
    Source_Scale_Denominator: 500000
    Source_Contribution: line features

    none (source 3 of 4)
    Greene, Amelia V., 1990, Illinois Geographic Information System: An Index to Automated Statewide Databases: Illinois State Water Survey Circular 175, Illinois State Water Survey, Champaign, Illinois.

    Type_of_Source_Media: paper
    Source_Scale_Denominator: n/a
    Source_Contribution:
    Catalog data and description of related GIS data sets, used in determination of GIS structure of this data set.

    none (source 4 of 4)
    Treworgy, Janis D., 1981, Structural Features in Illinois - A Compendium: ISGS Circular 519, Illinois State Geological Survey, Champaign, Illinois.

    Type_of_Source_Media: paper
    Source_Scale_Denominator: n/a
    Source_Contribution: unknown

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

    Date: 1994 (process 1 of 6)
    The maps were digitized using a large format (48x60 inch) Calcomp 9100 digitizer. The digitizing was started April 7th, 1994 and completed April 11th, 1994. The weed tolerance was always set at zero during digitizing. The arcsnap was 100 feet for the line coverages. The nodesnap was 50 feet for the line coverages. The above arc and node snap distances were used in order to be certain that arcs would snap on themselves for polygon closure (eg. 2000 feet), and so the lines would not snap to themselves when short isolated arcs without closure (eg. 100 feet) were required. These tolerances prevented lines and points from snapping to themselves or other features.

    Date: 1994 (process 2 of 6)
    A base map for digitizing was created by setting tics at the intersection of latitude / longitude lines (1 degree by 1 degree) between 88 and 91 degrees west longitude and 37 to 42 degrees north latitude. These tics were used along with reference marks on the mylar separates to coordinate the base map with the mylar map separates containing geologic structural features.

    Date: 1994 (process 3 of 6)
    The root mean squared (rms) error during digitizing was between 0.004 and 0.008 digitizer inches. The registration points (tics) used for digitizing this map are as follows:

    TIC # N. Latitude (degrees) W. Longitude (degree)

    06 ~ 37 91 51 37 90 53 ~ 37 88 20 ~ 42 91 23 ~ 42 88 26 41 91 29 41 88 32 40 91 35 40 88 38 39 91 41 39 88 45 38 90 47 38 88

    Note: a ( ~ ) tilde indicates the primary tics used for the statewide map.

    Date: 1994 (process 4 of 6)
    Line features were attributed using information from Plate 1 of ISGS Bulletin 100.

    Date: 1994 (process 5 of 6)
    In 1994-95 the coverage underwent extensive QA/QC (Quality Assurance / Quality Control) review. QA/QC was performed using paper-plots of the map to overlay on the original mylar map, on-screen checking, and data tables of the feature item values for comparing to the original map and publication. These operations were performed and reviewed by several individuals.

    Date: 31-Mar-2004 (process 6 of 6)
    Source coverages (struct*) converted to double precision and reprojected to GCS_NAD83 using Workstation ArcInfo 7.2.1.

    The features were imported into the ISGS SDE enterprise database following steps outlined in ISGS procedure GISDB_0009.

    Metadata updated.

    Person who carried out this activity:

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

    , ISGS Terms of Use.

    Online Links:

    , University of Illinois Web Privacy Notice.

    Online Links:

    , University Copyright Policy (stated in the General Rules Concerning University Organization and Procedure, Article III, Section 4).

    Online Links:

    , Policy on Appropriate Use of Computers and Network Systems at the University of Illinois at Urbana-Champaign.

    Online Links:

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

  1. How well have the observations been checked?

    The published (Plate 1) map from ISGS Bulletin 100 was the source for feature attributes. Attribute code assignments were checked by three individuals and are believed to fully representative of the source document.

  2. How accurate are the geographic locations?

    Horizontal positional accuracy of this data with respect to the source map was verified by three individuals by visual comparison (manual overlay) of source maps and hard-copy plots. Arcs within one line-width of source mylars were deemed acceptable. Consult Bull. 100 and its sources for information on the derivation of structure locations.

  3. How accurate are the heights or depths?

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

    These four feature classes together show all well documented significant structures in Illinois as defined by ISGS Bull. 100.

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

    When the dataset was stored as a coverage it was checked for complete chain-node topology (no dangling arcs, except where appropriate), boundary values appropriate for map projection and map units, and appropriate "fuzzy" tolerances. There are no known arc attribute values outside the appropriate value domains.

How can someone get a copy of the data set?

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

Access_Constraints:
ISGS information must be obtained directly from the ISGS or from an authorized distributor. Be aware that ISGS information obtained from an unauthorized third party may have been altered subsequent to original distribution, or may no longer be current.

Any access to these data, Web sites, computer systems, electronic services, and electronic networks is governed by University and campus policies, in particular, but not limited to, the Policy on Appropriate Use of Computers and Network Systems at the University of Illinois at Urbana-Champaign, the ISGS Terms of Use document available at the ISGS Web site, and the University of Illinois Web Privacy Notice.

Links to these are provided in the Cross References section.

Use_Constraints:
ISGS information is the property of and copyrighted by the Board of Trustees of the University of Illinois with all rights reserved.  University copyright policy is stated in the General Rules Concerning University Organization and Procedure, Article III, Section 4. A link is provided in the Cross References section.

Individuals or entities may make fair use of copyrighted ISGS material, such as reproducing a single figure or table, or using a brief text quotation, without obtaining formal permission, but in all cases the Illinois State Geological Survey must be credited as the source of the material. To reproduce ISGS information beyond the fair use standard, permission must be obtained from the ISGS Information Office, 615 East Peabody Drive, Champaign, Illinois 61820, 217-333-4747, isgs@isgs.illinois.edu. License fees and a license agreement may be required, depending on the proposed usage.

Any use of these data is governed by University and campus policies, in particular, but not limited to, the Policy on Appropriate Use of Computers and Network Systems at the University of Illinois at Urbana-Champaign, the ISGS Terms of Use document available at the ISGS Web site, and the University of Illinois Web Privacy Notice. Links to these are provided in the Cross References section.

Map information is to be used at a scientifically and cartographically appropriate scale, that is, at a scale no greater than indicated on the map or as described in the documentation of the map or map data.  Map information is not appropriate for, and is not to be used as, a geodetic, legal, or engineering base. Map information has no legal basis in the definition of boundaries or property lines and is not intended as a substitute for surveyed locations such as can be determined by a registered Public Land Surveyor.

The data do not replace the need for detailed site-specific studies.

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

    Information Office, Illinois State Geological Survey (ISGS), a division of the Institute of Natural Resource Sustainability (INRS) of the University of Illinois
    615 East Peabody Drive
    Champaign, Illinois 61820
    USA

    217-333-4747 (voice)
    isgs@isgs.illinois.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?

    Refer to the Legal Notices of Terms and Conditions of the University of Illinois Web Privacy Policy (there is a link in the Cross References section) for policy statements regarding the following:

    Disclaimer of Liability Disclaimer of Warranties and Accuracy of Data Disclaimer of Endorsement Disclaimer for External Links Disclaimer of Duty to Continue Provision of Data Security Choice of Law

    By obtaining these data you agree to the provisions of the University of Illinois Web Privacy Policy, regardless of the manner in which the information was obtained.

  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, ESRI formats can be imported into many different GIS software packages. It is expected that customers who obtain these 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: 24-Feb-2009
Metadata author:

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

Illinois Natural Resources Geospatial Data Clearinghouse

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