Illinois State Geological Survey 1994 20040423 vector digital data ISGS GIS Database GISDB_QTGEO.IL_Drift_Thickness Champaign, Illinois Illinois State Geological Survey http://www.isgs.illinois.edu/ http://illinois.edu This is an SDE feature dataset showing drift thickness in Illinois. Data are originally from ISGS Circular 490 by Piskin and Bergstrom (1975), Plate 1. Contours (lines) are coded with thickness, and polygons (areas between contours) are coded with range of thickness. Nominal scale is 1:500,000. Unconsolidated deposits, mainly glacial drift, overlie the bedrock surface in most of Illinois. Glacial drift ranges from less than a few feet to approximately 600 feet in thickness. The thickest drift occurs in major preglacial valleys cut into the bedrock and filled with glacial sediments. Regionally thick drift occurs in the N.E. portions of the state. The thinnest drift, less than 25 feet thick and intersected by numerous bedrock outcrops, occurs widely in southern and western portions of the State. Drift, as shown on this map, may include any of the following: unconsolidated deposits, glacial drift, Wisconsinan deposits, Illinoian deposits, till, glaciofluvial deposits, glaciolacustrine deposit, wind-blown deposits (loess). These data may be used to determine approximate depth to bedrock in regional areas of the state (eg. townships). The data are not of sufficient detail for use in determining drift thickness for specific locations. The data can be used for physical or environmental models of the state's unconsolidated geologic materials, eg. coupled with geophysical information, satellite imagery, air photos, hydrologic data, or other data in a Geographic Information System at a statewide 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. Recent updates to the data: In April 2004 edition 2.0 of the data set was transitioned to storage in an Oracle RDBMS using the ArcSDE geodatabase model. The result (this version) is designated Edition 20040423. Edition 1.0 of this data set was replaced edition 2.0 in June, 1998. The data were reviewed as described in the logical consistency report and process steps for May, 1998. Contour values, which were not included in edition 1.0, were included in version 2.0. 199410 Latest updates were made in 1994. Most of the data still reflect ISGS Circular 490 (1975). Complete Irregular -91.513518 -87.495214 42.508348 36.969972 none glacial drift unconsolidated till glaciofluvial glaciolacustrine loess driftless none Illinois none Wisconsinan Illinoian 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. 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. Please refer to the Distribution Information section. ArcSDE 9.1 on Oracle 10g http://www.isgs.illinois.edu http://www.vpaa.uillinois.edu/policies/web_privacy.cfm http://www.uillinois.edu/trustees/rules.cfm#sec34 http://www.fs.uiuc.edu/cam/CAM/viii/viii-1.1.html Attributes were verified against information on the source map by using polygon shading tied to attribute values. Checks were also performed by relating polygon and arc attribute tables and comparing polygon drift thickness range codes with arc drift thickness values. These checks were reiterated by three individuals. There are no known polygon or arc attribute values outside the appropriate domains. There were, however, some anomalous values discovered on the primary source map (Piskin and Bergstrom, 1975, Plate 1) that have been retained in this data set. See logical consistency report. Polygon and chain-node topology was present in the source coverage. It was checked for complete chain-node topology (no dangling arcs, except where appropriate), polygon labels (one per polygon, except for universal polygon), boundary values appropriate for map projection and map units, and appropriate "fuzzy" tolerances. The data set meets these parameters. However, there exists at least one instance of anomalous contour labeling on the source map and in this data set. A pair of concentric contours exist in west-central Woodford County which should have a third contour around them labeled 100 feet. The missing contour does not appear on the source mylar for the map. The anomaly could not be reconciled, so it was left as it appeared on the original map. See the small "bulls-eye" contour in west-central Woodford County. See Piskin and Bergstrom (1975), ISGS Circular 490. Horizontal positional accuracy was verified by visual overlay of source and hard-copy plots. Arcs within line-width of source maps were deemed acceptable. For positional accuracy of source maps, see Piskin and Bergstrom (1975), ISGS Circular 490. Kemal Piskin & Robert E. Bergstrom 1975 map ISGS Circular 490 Champaign, Illinois Illinois State Geological Survey 500,000 paper 1975 publication date none polygon attributes Kemal Piskin & Robert E. Bergstrom 1975 map Champaign, Illinois Illinois State Geological Survey unpublished material 500,000 mylar 1975 publication date none drift thickness contours Environmental Systems Research Institute, Redlands CA 1984 maps and report 500000 paper 198411 publication date none data history The data (lines) were originally digitized and attributed by Environmental Systems Research Institute in 1984. 1984 The data was compared to the original mylar map at ISGS from the Circular 490 publication, and edits were made to make the digital map match the original mylar. Attribute coding remained the same. Editing was performed on a digitizing board using the original tics or registration points for the statewide coverage. 1984 The data set underwent quality assurance review in 1994. Many lines were smoothed and densified to provide a better match to the source mylars. In McDonough, Knox, and Fulton counties significant line edits were made where the digital lines did not match the mylar original (in most cases, due to collapsed arcs and/or carrying contours). 1994 Data set was reviewed in May, 1998. Review was limited to internal logical consistency of attribute items. Locations of features and accuracy of item values were not checked, except in cases where possible errors became apparent as a result of logical consistency checks. No checks were performed that involved plotting of hardcopy maps and manual overlay with source materials. Some changes were made, as follows: Arcs were coded with contour values. This was done with an AML program that assigned contour values to arcs based on the drift thickness values for the adjacent polygons. This processing was done in late 1996, but the updates were not posted to the general-use data set until June of 1998. The existing set of tics was replaced by the set of tics from the coverage RE-STATE1. These were derived from 7.5 minute quadrangle corners (data set QUAD75) and give a good distribution of tics immediately outside the state boundary. COVER-ID values were recalculated to be unique. 199806 199806 Source coverage (driftthk) 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. 20040423 Vector G-polygon 1354 String 2006 0.000001 0.000001 Decimal degrees North American Datum of 1983 Geodetic Reference System 80 6378137.000000 298.257222 GISDB_QTGEO.IL_Drift_Thickness_Py GISDB_QTGEO.IL_Drift_Thickness_Ln Attribute items are in typical SDE feature class format. Those requiring explanation are: Polygon Attributes: THICK - thickness of drift 1 - Less than 25 feet 2 - 25 to 50 feet 3 - 50 to 100 feet 4 - 100 to 200 feet 5 - 200 to 300 feet 6 - 300 to 400 feet 7 - 400 to 500 feet 8 - Greater than 500 feet Thick. 9 - No Drift (Driftless Regions) RANGE - range of thicknesses in feet for that polygon Arc Attributes: CONTOUR - The contour value for the arc. none Information Office, Illinois State Geological Survey (ISGS), a division of the Institute of Natural Resource Sustainability (INRS) of the University of Illinois mailing and physical address

615 East Peabody Drive

Champaign Illinois 61820 USA 217-333-4747 217-785-0211 isgs@isgs.illinois.edu 8:00 a.m. - 4:30 p.m., Monday-Friday, U.S. Central Time 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. 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. 20090224 Please refer to the Distribution Information section. FGDC Content Standards for Digital Geospatial Metadata FGDC-STD-001-1998 local time The access constraints as stated for the data apply also to the metadata. Refer to the Access Constraints section of the Identification Information section. The use constraints as stated for the data apply also to the metadata. Refer to the Use Constraints section of the Identification Information section. http://www.esri.com/metadata/esriprof80.html ESRI Metadata Profile