Illinois State Geological Survey, 1984, 199803, Township Center Points of Illinois: ISGS GIS Database townpts, Illinois State Geological Survey, Champaign, Illinois.Online Links:
- Downloadable Data (Shift-Click to download data file) <URL:http://www.isgs.uiuc.edu/nsdihome/browse/statewide/townpts.e00>
- Browse Graphic (GIF) Screen-size image representing the nature of the data. <URL:http://www.isgs.uiuc.edu/nsdihome/browse/statewide/townptsb.gif>
- Text (.txt) version of this Metadata file. (Shift-Click to download documentation) <URL:http://www.isgs.uiuc.edu/nsdihome/outmeta/townpts.txt>
- HTML (.html) version of this Metadata file. (Shift-Click to download documentation) <URL:http://www.isgs.uiuc.edu/nsdihome/outmeta/townpts.html>
This is a Point data set. It contains the following vector data types (SDTS terminology):
The map projection used is Lambert Conformal Conic.
Planar coordinates are encoded using coordinate pair
Abscissae (x-coordinates) are specified to the nearest unknown
Ordinates (y-coordinates) are specified to the nearest unknown
Planar coordinates are specified in feet
The horizontal datum used is NAD27.
The ellipsoid used is CLARKE1866.
The semi-major axis of the ellipsoid used is 6378206.4 meters.
The flattening of the ellipsoid used is 1/294.98.
Attribute items are in typical ARC/INFO feature class format. POINT ATTRIBUTES: Point attributes indicate meridian, township, range, x-coordinates, and y-coordinates. Point items other than the Arc/Info defaults are: MERIDIAN - The meridian of the township TOWNSHIP - The alphanumeric township identifier RANGE - The alphanumeric range identifier X-COORD - X Coordinate of the center of the township in Lambert feet Y-COORD - Y Coordinate of the center of the township in Lambert feet ** REDEFINED ITEMS ** TWP - The condensed meridian, township and range identifier TNUM - The numeric township identifier RNUM - The numeric range identifier
GIS Processing: ISGS Staff, C. Abert, D. Nelson Documentation: D. Nelson and S. Beaverson Quality Control: ISGS Staff, D. Nelson
217-333-4747 (voice)
217-244-0802 (FAX)
isgs@isgs.uiuc.edu
This data set was created to serve as base map information at scales of 1:62,500 or smaller. Attribute data identify township and range. These data are appropriate for use in local and regional thematic analysis. Data are not appropriate as a geodetic or engineering base.
Illinois State Geological Survey, 1984, Illinois Public Land Survey System: ISGS GIS Database re-state1.Online Links:
- Data Set Documentation <URL:http://www.isgs.uiuc.edu/nsdihome/outmeta/re-state1.html>
TICS - The data set had four tics well placed around the state. To conform with other illimap data sets, however, these were replaced with ten tics from *path_name_suppressed*/quad100, evenly distributed around the state. These provide a slightly better tic coverage. However, users needing registration tics for use with these data (or a subset of these data) should expect to create a task-specific tic set, usually based on section corners.
REMOVAL OF ITEMS - .PAT item TRS was removed. It is a remnant from coverage RE-STATE1 that is not necessary in this data set.
UNIQUE COVER-ID VALUES - COVER-ID values in the .PAT were calculated to equal (COVER# - 1) in order to make them unique.
EXTRA POINTS - Two extra points were removed. TOWNPTS# = 876 in .PAT had TWP = '4 2N 2E'. This point should actually be a part of the polygon to the immediate west (RE-STATE1# = 57698, TRS = '4 2N 1E25'). See metadata for RE-STATE1 or TOWNSHIPS for a complete explanation. Meridian, township, range and section designation were verified by D. Nelson and C. Abert using 1997 and 1998 plat map books for Mason and Schuyler Counties. TOWNPTS# = 1 was also removed. This point relates to the universe polygon in TOWNSHIPS, but is not a township center point. (The ID numbers in this paragraph refer to edition 1.0 of the data, not the current edition. For verification, see the archived data set in *path_name_suppressed*/illimap_v1_0.)
For detailed review see *path_name_suppressed*/illimap_v1_0_rev.txt.
Illinois State Geological Survey, 1984, 199803, State Line Boundary of Illinois: ISGS GIS Database state, Illinois State Geological Survey, Champaign, Illinois.Online Links:
- Data Set Documentation <URL:http://www.isgs.uiuc.edu/nsdihome/outmeta/state.html>
Illinois State Geological Survey, 1984, 199803, Illinois County Boundaries: ISGS GIS Database counties, Illinois State Geological Survey, Champaign, Illinois.Online Links:
- Data Set Documentation <URL:http://www.isgs.uiuc.edu/nsdihome/outmeta/counties.html>
Illinois State Geological Survey, 1984, 199803, Township Lines of Illinois: ISGS GIS Database townships, Illinois State Geological Survey, Champaign, Illinois.Online Links:
- Data Set Documentation <URL:http://www.isgs.uiuc.edu/nsdihome/outmeta/townships.html>
Illinois State Geological Survey, 1984, 199803, Indian Treaty Boundary Lines of Illinois: ISGS GIS Database indianlns, Illinois State Geological Survey, Champaign, Illinois.Online Links:
- Data Set Documentation <URL:http://www.isgs.uiuc.edu/nsdihome/outmeta/indianlns.html>
This coverage was extracted from coverage re-state1, the primary public land survey data set in the ISGS GIS database. The attributes of that coverage were reviewed in 1990 using a variety of visual techniques (polygon shading, line shading and line thicknesses tied to attribute values) and GIS processing techniques (checking for logical consistency). See the metadata for re-state1 for a more complete description of this review. There is no quantitative assessment of attribute accuracy available, however, this coverage has been used extensively by ISGS personnel since 1984, and it can be assumed most attribute errors have been detected and corrected. There are no arc attribute values outside the appropriate value domains.
These points were centered on township polygons in the ISGS GIS database coverage re-state1 using the ARC/INFO CREATELABELS command. They are intended for general centering of map labels. No specific determination of horizontal positional accuracy is available. These points do not represent an accurate physical ground condition.
This data set contains one center point for each township in Illinois.
A logical consistency review was performed in March, 1998. The following checks were made:
Data set was DESCRIBED and coverage files listed to determine the feature types present. In this data set, the following feature types were found and checked: points. The presence of spatial indices was also checked.
For PAT files, each ITEM was checked for the following:
- DOMAIN of allowable values - adherence of values to the DOMAIN - definition of ITEMS - requirement of all UNIQUE values for an item - logic of ITEMS REDEFINED over other ITEMS - length of ITEM name as regards conversion to shape fileBUILD statuses of data sets were checked, as were LABELERRORS and NODEERRORS (where appropriate), and PROJECTION definition.
The presence of a BND file was verified.
The presence and location of TICS were checked.
Point topology present. There is one point for each corresponding polygon in *path_name_suppressed*/townships. Boundary values are appropriate for map projection and map units. "Fuzzy" tolerance is suitable for nominal scale. Two unneeded points were dropped, one .PAT item was dropped, and tics were replaced. COVER-ID values were recalculated to be unique. See process steps for March, 1998. There are no attribute values outside the appropriate domains.
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 the appropriate custodial division within 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.
These data are not to be used for commercial profit.
217-333-4747 (voice)
217-244-0802 (FAX)
isgs@isgs.uiuc.edu
An Arc/Info .e00 (export) file is currently available free of charge at the Illinois Natural Resources Geospatial Data Clearinghouse. Refer to the Citation Information portion of this file for access to downloadable data and metadata, and a visual (GIF image) representation of the data. Shift-click to download the data set and related documentation. (Data and metadata offered separately, please download both files.)
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.
217-333-4747 (voice)
217-244-0802 (FAX)
isgs@isgs.uiuc.edu
Illinois Natural Resources Geospatial Data Clearinghouse
Generated by mp version 2.8.11 on Mon Jan 29 15:19:45 2007