Stack-unit maps show the distribution of earth materials vertically from the surface to a specified depth and horizontally over a specified area They also show the succession of geologic units in their order of occurrence within the specified depth. This information is now available for the entire state of Illinois with the publication of the statewide stack-unit map of geologic materials to a depth of 15 meters (49.3 ft.).
The statewide stack-unit map, originally made up of four separate regional maps, provides basic geologic information for interpretive mapping for regional, resource-based land-use planning and decision making. This feature class is the result of appending the four separate digital files into one statewide dataset. Note also that this feature class incorporates stack-unit data from the ISGS Paducah Stack-Unit map (Berg and Greenpool, 1994). The portion that falls within the 1 x 2 degree Paducah quadrangle had been entirely updated with data from the Paducah stack-unit map coverage.
In April 2004 edition 2.1 of the data set was transitioned to storage in an Oracle RDBMS using the ArcSDE geodatabase model. The result (this version) is designated Edition 20040422.
Edition 2.0 of these data were reviewed for internal logical consistency in June, 1998. As a result, tics were replaced, COVER-ID values were recalculated to be unique, and an empty annotation feature class was dropped. The updated data set was edition 2.1.
Mspgm.doc is an INFO program that reads STACK-UNIT item values (redefined as UNIT1, QUAL1, UNIT2, QUAL2, UNIT3, QUAL3, UNIT4, QUAL4, UNIT5, QUAL5) and writes the corresponding MS (MAP-SYMBOL) item values (redefined as MS1, MS2, MS3, MS4, MS5) to the .PAT file. (See the Entity and Attribute Information section for an explanation of these items.) The program was written by Don Keefer of the ISGS. It also requires two INFO dictionary files: dic and dic3. Although these program and dictionary files are no longer available on the ISGS computer system, it is possible they could be recovered from back-up tapes if necessary (the possibility of recovery, of course, diminishes with time.)
Illinois State Geological Survey, 1995, Stack-Unit Mapping of Geologic Materials in Illinois to a Depth of 15 Meters: ISGS GIS Database GISDB_QTGEO.IL_Stack_Units_To_15m_Py, Illinois State Geological Survey, Champaign, Illinois.
This is a Vector data set. It contains the following vector data types (SDTS terminology):
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.
STACK-UNIT The STACK-UNIT item is a 15 digit numeric code that describes up to five geologic units present, their order of occurrence, and general thickness and depth. It is directly related to item MS in that MS is an alphanumeric designator that represents the same information as STACK-UNIT. STACK-UNIT consists of ten concatenated (redefined) items called (and in this order) UNIT1, QUAL1, UNIT2, QUAL2, UNIT3, QUAL3, UNIT4, QUAL4, UNIT5, QUAL5. UNITx (where x is 1, 2, 3, 4, or 5) is a 2 digit field unit name (see the table below). QUALx is a qualifier for each UNITx, giving thickness, depth and continuity information for the corresponding UNITx. For example, QUAL1 contains a code that gives descriptive information for UNIT1. UNIT1 is the uppermost unit, UNIT5 is the lowermost unit.
TABLE OF ITEM RELATIONSHIPS UNITx MSx Corresponding Geologic Unit (MAP-SYMBOL)
(nonlithified and semilithified materials) 1 A a* Cahokia Alluvium 2 Y y* Peyton Colluvium 3 B b* Richland Loess 4 C c* Peoria and Roxana Loess 5 D d* Parkland Sand 6 E e* Grayslake Peat 7 F f* Equality Formation, Carmi Member 8 G g* Equality Formation, Dolton Member 9 H h* Henry Formation 10 I i* Wedron Formation, silty and clayey diamictons 11 J j* Wedron Formation, loamy and sandy diamictons 12 K Sand and gravel within Wedron Formation: 12 k* within 6 m (19.7 ft.) of surface 26 z* between 6-15 m (19.7-49.3 ft.) of surface 13 L l* Winnebago Formation, mainly sandy diamictons 14 M Sand and gravel within Winnebago Formation: 14 m* within 6 m (19.7 ft.) of surface 26 z* between 6-15 m (19.7-49.3 ft.) of surface 15 N n* Teneriffe Silt 16 O o* Pearl Formation (includes Hagarstown Member) 17 P p* Glasford Formation, silty and clayey diamictons 18 Q q* Glasford Formation, loamy and sandy diamictons 19 R Sand and gravel within Glasford Formation 19 r* within 6 m (19.7 ft.) of surface 26 z* between 6-15 m (19.7-49.3 ft.) of surface 22 U u* Wolf Creek Formation (mainly diamictons) 23 V v* Mounds gravel and related units 24 W w* Cretaceous sediments, silts, sands, etc. 25 X Surface mines/man-made land
(lithified materials) 41 1 1* Pennsylvanian rocks, mainly shales 42 2 2* Pennsylvanian rocks, mainly sandstones 43 3 3* Mississippian rocks, mainly shales 44 4 4* Mississippian rocks, mainly limestones, some sandstones 45 5 5* Silurian and some Devonian rocks, mainly dolomite 46 6 6* Ordovician rocks, mainly shale (Maquoketa Group) 47 7 7* Ordovician and Cambrian rocks, mainly dolomite, some sandstone
other 98 water body of water
QUALx 1 Drift unit > 6m thick, continuous throughout map area 2 Drift unit > 6m thick, locally less than 6m thick 3 Drift unit < 6m thick, continuous throughout map area 4 Drift unit < 6m thick, not continuous throughout map area
6 Bedrock unit present between 6 and 15 meters below surface 7 Bedrock unit not present continuously between 6 and 15 meters below surface; locally present at or just below 15 meters 8 Bedrock unit present within 6 meters of surface 9 Bedrock unit not present continuously above 6 meters below surface; but then is present between 6-15 meters
MS Item MS is the map symbol for each polygon. It is an alphanumeric character set that describes up to five geologic units present, their order occurrence, and general thickness and depth. Item MS is directly related to item STACK-UNIT in that STACK-UNIT is a strictly numeric designator that represents the same information as item MS. MS consists of five concatenate (redefined) items called MS1, MS2, MS3, MS4, MS5. Each redefined MSx (where x is 1, 2, 3, 4, 5) item represents a single geologic unit, MS1 being the uppermost and MS5 being the lowermost. Uppercase letters indicate nonlithified a semilithified units greater than 6m (19.7 ft.) thick. Lowercase letters accompanied by asterisk indicate nonlithified and semilithified units less than 6m (19.7 ft.) thick. Numbers unaccompanied by an asterisk indicate lithified units where the top occurs between depths of 6-15m (19.7-49.3 ft.) below ground surface. Numbers accompanied by an asterisk indicate lithified units where the top occurs between depths of 0-6m (0-19.7 ft.) below ground surface.
Some units are of varying thickness; this is represented by parentheses. An uppercase letter enclosed by parentheses indicates the unit is continuous throughout the map area but less than 6m thick in some areas. If the unit is lowermost, it may not be present above the 15m depth, but generally lies at just below 15m.
A lowercase letter (with asterisk) enclosed by parentheses indicates the unit is not continuous throughout the map area. If the unit is lowermost it may not be present above the 15m depth, but generally lies at or just below 15m.
A number (without asterisk) enclosed by parentheses indicates the unit may not be present above the 15m depth, but generally lies at or just below that depth.
A number (with asterisk) enclosed by parentheses indicates the unit may not be continuous in the map area within 6m of surface, but is present between depths of 6-15m over a portion of the map area.
Refer to the table above for the relationship between MS, STACK-UNIT, and name of the corresponding geologic unit.
The general concept of a stack-unit map is that once the arrangement of geologic deposits is established within a framework of controls (data and geologic concepts), materials can be evaluated in terms of their industrial mineral resource potential and hydrogeologic and engineering properties. Because stack-unit maps are also stratigraphic maps, they can provide clues to many aspects of geologic history that occurred prior to events represented by surficial mapping.
Depth is a significant factor for most resource and land-use interpretations derived from stack-unit data. For example, in the evaluation of sites for municipal landfills, geologic material to a depth of 15 meters should be documented. For near-surface or surficial waste-disposal practices, for evaluation of materials for shallow construction purposes, or assessment of recharge, detailed information in the upper 6 meters is usually the most important. For mineral resource evaluation, the thickness of overburden and thickness and character of the resource must be considered. Likewise, for shallow groundwater resource evaluation, the thickness, continuity, and depth of an aquifer, as well as the properties of overlying materials, must be recognized.
Statewide stack-unit data have been used to produce interpretive maps for projects such as municipal, surface and near surface waste disposal (susceptability to contamination), and shallow aquifer identification. They can be used to appraise (1) regional geologic conditions, (2) general geologic conditions that might affect excavation and construction of roads, pipelines or sewers, and (3) possible locations of mineral resources, particularly sand and gravel, clay, peat, limestone and dolomite.
This feature class is appropriate for use at scales of 1:250,000 and smaller.
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.
Berg, R.C. and J.P. Kempton, 1988, Stack-Unit Mapping of Geologic Materials in Illinois to a Depth of 15 Meters: ISGS Circular 542, Illinois State Geological Survey, Champaign, Illinois.
Berg, R.C. and J.P. Kempton, 1988, unpublished, Mylar Separates Used to Produce Map Plates for Stack-Unit Mapping of Geologic Materials in Illinois to a Depth of 15 Meters.
Anderson, R.C., 1980, Geology for planning in Rock Island County, Illinois: ISGS Circular 510, Illinois State Geological Survey, Champaign, Illinois.
Berg, R.C., J.P.Kempton, L.R. Follmer, and , 1985, Illinoian and Wisconsinan stratigraphy and environments in northern Illinois: the Altonian revised.: ISGS Guidebook 19, Illinois State Geological Survey, Champaign, Illinois.
Berg, R.C., J.P. Kempton, and A.N. Stecyk, 1984, Geology for planning in Boone and Winnebago Counties: ISGS Circular 531, Illinois State Geological Survey, Champaign, Illinois.
Berg, R.C., J.P. Kempton, and K. Cartwright, 1984, Potential for contamination of shallow aquifers in Illinois: ISGS Circular 532, Illinois State Geological Survey, Champaign, Illinois.
Bergstrom, R.E., 1970, Geology for planning at Crescent City: ISGS Environmental Geology Notes 36, Illinois State Geological Survey, Champaign, Illinois.
Bergstrom, R.E., K. Piskin, and L.R. Follmer, 1976, Geology for planning in the Springfield-Decatur region, Illinois: ISGS Circular 497, Illinois State Geological Survey, Champaign, Illinois.
Gross, D.L., 1970, Geology for planning in DeKalb County, Illinois: ISGS Environmental Geology Notes 33, Illinois State Geological Survey, Champaign, Illinois.
Hackett, J.E. and M.R. McComas, 1969, Geology for planning in McHenry County: ISGS Circular 438, Illinois State Geological Survey, Champaign, Illinois.
Hines, J.K., 1986, Siting the superconducting super collider in northeastern Illinois: Environmental Screening Atlas: Illinois State Geological Survey, Champaign, Illinois.
Hunt, C.S. and J.P. Kempton, 1977, Geology for planning in De Witt County, Illinois: ISGS Environmental Geology Notes 83, Illinois State Geological Survey, Champaign, Illinois.
Jacobs, A.M., 1971, Geology for planning in St. Clair County, Illinois: ISGS Circular 465, Illinois State Geological Survey, Champaign, Illinois.
Kempton, J.P., 1981, Three-dimensional geologic mapping for environmental studies in Illinois: ISGS Environmental Geology Notes 100, Illinois State Geological Survey, Champaign, Illinois.
Kempton, J.P. and K. Cartwright, 1984, Three-dimensional geologic mapping: A basis for hydrogeologic and land-use evaluations.: Bulletin of the Association of Engineering Geologists unknown, unknown, unknown.
Kempton, J.P., J.E. Bogner, and K. Cartwright, 1977, Geology for planning un northeastern Illinois VIII, Regional Summary: ISGS Open File Report OFS 1977-2, Illinois State Geological Survey, Champaign, Illinois.
Kempton, J.P., W.J. Morse, and A.P. Visocky, 1982, Hydrogeologic evaluation of sand and gravel aquifers for municipal groundwater supplies in east-central Illinois: ISGS Cooperative Groundwater Report 8, Illinois State Geological Survey, Champaign, Illinois.
Kempton, J. P., R. W. Ringler, P. C. Heigol, 1981, Groundwater resources of northern Vermilion County, Illinois: ISGS Environmental Geology Notes 101, Illinois State Geological Survey, Champaign, Illinois.
Kolata, D.R. and A. Graese, 1983, Lithostratigraphy and depositional environments of the Maquoketa Group (Ordovician) of northern Illinois: ISGS Circular 528, Illinois State Geological Survey, Champaign, Illinois.
Larsen, J.I., 1973, Geology for planning in Lake County, Illinois: ISGS Circular 481, Illinois State Geological Survey, Champaign, Illinois.
LeSeur, L., 1985, Geohydrology of ground-water contamination: in An Assessment of Groundwater Quality and Hazardous Substance Activities in Illinois with Recommendations for a State-wide Monitoring Strategy: contract report 367, Illinois State Water Survey, Champaign, Illinois.
Lineback, J.A., 1979, Quaternary Deposits of Illinois: ISGS Map unknown, Illinois State Geological Survey, Champaign, Illinois.
McComas, M.R., 1968, Geology related to land-use in the Hennepin region: ISGS Circular 422, Illinois State Geological Survey, Champaign, Illinois.
McComas, M.R., K. C. Hinkley, and J.P. Kempton, 1969, Coordinated mapping of geology and soils for land-use planning: ISGS Environmental Geology Notes 29, Illinois State Geological Survey, Champaign, Illinois.
Miller, J.R., R.C Berg, T.M.Johnson, and H.A., 1985, Siting a low-level radioactive waste disposal facility in Illinois: State-wide criteria: IL Dept. of Nuclear Safety, Illinois.
Piskin, K, and R.E. Bergstrom, 1975, Glacial drift in Illinois: Thickness and character: ISGS Circular 490, Illinois State Geological Survey, Champaign, Illinois.
Willman, H.B., 1967, Geologic Map of Illinois: ISGS Map none, Illinois State Geological Survey, Champaign, Illinois.
Willman, H.B. and J.C. Frye, 1970, Pleistocene stratigraphy of Illinois: ISGS Bulletin 94, Illinois State Geological Survey, Champaign, Illinois.
Willman H. B., E. Atherton, T. C., Buschbach, C. , 1975, Handbook of Illinois Stratigraphy: ISGS Bulletin 95, Illinois State Geological Survey, Champaign, Illinois.
Willman, H.B. and D.R. Kolata, 1978, The Platteville and Galena Groups in northern Illinois: ISGS Circular 502, Illinois State Geological Survey, Champaign, Illinois.
Berg, R.C. and M.R. Greenpool, 1994, Stack-unit of Paducah 1x2 degree quadrangle: geologic materials to a depth of 15 meters: ISGS Map unknown, Illinois State Geological Survey, Champaign, Illinois.
Berg, R.C. and M.R. Greenpool, 1995, Paducah Stack-Unit Map (UTM16): ISGS GIS database ps20, Illinois State Geological Survey, Champaign, Illinois.
Illinois State Geological Survey, unknown, Stack-Unit Map Plate 1: ISGS GIS database stack1, Illinois State Geological Survey, Champaign, Illinois.
Illinois State Geological Survey, unknown, Stack-Unit Map Plate 2: ISGS GIS database stack2, Illinois State Geological Survey, Champaign, Illinois.
Illinois State Geological Survey, unknown, Stack-Unit Map Plate 3: ISGS GIS database stack3, Illinois State Geological Survey, Champaign, Illinois.
Illinois State Geological Survey, unknown, Stack-Unit Map Plate 4: ISGS GIS database stack4, Illinois State Geological Survey, Champaign, Illinois.
Significant revision was made to the stack4 coverage. These changes are detailed below.
The source coverages underwent a QA/QC review in Summer, 1995. During that review, several inconsistencies between the published version of Stack4 and the automated coverage of STACK4 were revealed. It was learned from ISGS geologists Dick Berg, Don Keefer and Mary Greenpool that during the period 1989-91 the STACK4 automated coverage had been updated with a partial set of data derived from the Paducah stack-unit coverage called PS20. The PS20 coverage overlaps (approximately) the southern half of the STACK4 coverage, and includes stack-units which are derived in part from data which are more recent and at a greater level of detail than that in STACK4.
Because a partial update had been performed on STACK4 there existed no original map (workmap, published map, etc.) to check the STACK4 coverage. That is, comparing STACK4 against either the published version of Stack4 or the published version of the Paducah stack-unit map would result in inconsistencies; it would be indeterminate whether the inconsistencies were errors or intended updates.
It was decided by committee to fully update the STACK4 coverage with the PS20 coverage. The portion of STACK4 that is not overlapped by PS20 would be verified against the published version of Stack4. The portion of STACK4 that was updated (i.e. replaced) by PS20 would be compared with the published version of the Paducah stack-unit map.
The processing used to create the updated Stack4 coverage is as follows:
7-20-94 The two coverages to be joined are stack4 and ps20. They have differing sets of items in the .PAT info files and different schemes for the coding of the item MS, which is the alphanumeric stack-unit label.
According to Mary Greenpool, however, the 12 digit STACK- UNIT items, from which MS codes are derived, and which appear in both .PAT files, use the same coding scheme. Thus, it should be a simple matter to write an INFO program to convert the MS codes in PS20 to the appropriate scheme for STACK4
7-25-94 Received from Don Keefer an info program (called MSPGM) that will do the necessary conversion of MS codes.
7-26-94 Input MSPGM (manually) into computer.
7-27-94 Built the dictionary files DIC2 and DIC3 for use with MSPGM. These files are used to assign the appropriate MS codes based on the STACK-UNIT values.
7-28-94 Testing MSPGM: Created a test file called MSPGMTEST.PAT. This file contains 140 records selected from STACK4.PAT such that they are relatively evenly distributed spatially throughout the coverage. The item MS was renamed PRE-MS and a new item MS was created. The redefined items MS1, MS2, MS3, and MS4 were adjusted to relate to the new MS item. Program MSPGM was then run on this file, writing codes to item MS based on values in the item STACK-UNIT. Then the codes in MS were compared with PRE-MS to verify the reliability of the program. All 140 test records matched exactly.
PS20 is in a UTM16 projection. Transformed it into Lambert projection to conform to Stack4. Called new coverage PS20-LAM. See topology processing of 7-28-94.
7-29-94 Clip processing: Created a clip coverage by combining the appropriate boundary arcs from coverages state and PS20-LAM. Clip cover name is PSILBND. Used PSILBND to clip out the Illinois portion of PS20-LAM, creating coverage PSIL.
Ohio, Mississippi and Wabash River boundaries are present in PSIL but not in STACK4. They were removed from PSIL to conform to STACK4.
Copied PSIL to PSIL2 before updating the MS codes with program MSPGM. PSIL2 was prepared for processing in the same manner as the test file (see 7-28-94 above).
8-1-94 Found some UNIT2 & UNIT3 item values in PSIL.PAT that have values which are not used in STACK4.PAT (i.e. values of 30, 35, 53). See entry of 8-18-94 for solution to this problem.
In identifying the polygons related to the above problematic UNIT2 & UNIT3 item values, also found some sliver polygons. Corrected these slivers in PSIL. Thus, deleted PSIL2 and recopied PSIL to PSIL2, and again prepared PSIL2 for processing with MSPGM.
Ran MSPGM on PSIL2.
There are STACK-UNIT codes in PSIL2 that have values of 111111111111, representing mined areas. These were assigned temporary MS values of (999) for easy identification on plots. Similarly, STACK-UNIT = 980980980980 were assigned MS of 'lake'.
8-2-94 Combined the boundaries of PSIL2 and STACK4 to make a clip coverage called STK4SANSPAD which bounds all of STACK4 that is not a part of PSIL2. This clip coverage was used to create from STACK4 a coverage called STK4NOPAD which includes all of STACK4 that is not a part of the area covered by PSIL2.
In preparation of MAPJOIN of PSIL2 and STK4NOPAD, edited the definitions of the items in their .PAT files so that all items and item definitions are identical. The new list of items includes all items that were in either coverage.
MAPJOINed these two coverages, creating the coverage STACK4NEW. See topology processing of 8-2-94.
Renamed STACK4NEW to STACK4PAD and attempted a DISSOLVE to join like polygons across the join boundary. This was unsuccessful because no polygons have all values identical for every item. Therefore, STACK4PAD was renamed back to STACK4NEW and the remnant boundaries were removed manually.
8-5-94 The .PAT file for STACK4NEW contains over 40 items. According to Don Keefer, many of these were created for one-time usage (i.e. processing the coverage to highlight features that may have been helpful for separate projects), and can be removed. The following is a list of unnecessary items that were removed from STACK4NEW.PAT in order to streamline the coverage:
BRHSYMB1 BRH1 SYMBOL DIS BRHSYMB2 BRH2 PC4SYMBOL STACK BRHSYMB3 BRH3 PC4TEST UNIT BRHSYMB4 BRH4 SURFACE
Attempted another DISSOLVE on STACK4NEW. This time it was successful, creating coverage STACK4NEW2. See topology processing of 8-5-94.
As previously mentioned, some STACK-UNIT codes in PSIL2 had the value 111111111111 to indicate mined out areas. This is indicated in STACK4 with a STACK-UNIT code = 253000000000, and corresponding MS = X. In STACK4NEW2, records for mined out areas have been updated to use the STACK4 coding scheme. Also, for the sake of uniformity, all records that are intended to represent water were updated (if necessary) to STACK-UNIT = 980980980980 and MS = 'water'. Note this is the second time these records have been modified. (See entry for 8-1-94)
8-18-94 Refer to entry of 8-1-94. STACK-UNIT codes 30, 35, and 53 appear in the Paducah set of coverages but not in the Stack4 set. The 30 and 35 values in PS20 refer to sand and gravel within the Glasford formation and have corresponding MS designations of *o and O respectively; in STACK4 this is represented by the STACK-UNIT value 26 and MS designations z* and Z. These corrections were performed manually to conform to STACK4. In PS20, STACK- UNIT value 53 refers to MS designation T, being Tertiary deposits. According to Dick Berg, this is represented as Cretaceous on STACK4. Thus, these items were corrected to the STACK4 designators for Cretaceous sediments, which are STACK-UNIT = 24 and MS = w* or W.
At this point, the first step in the QA/QC review and update of STACK4 is complete.
10-6-94 Second review complete; four corrections to be made.
Also, there is one polygon on the original Stack4 map that has five units indicated. There are polys on the other Stack maps that indicate five units as well. In order to allow for these it was necessary to expand MS and STACK-UNIT items to accommodate five units each.
10-19-94 Made the modifications mentioned in 10-6-94 above. STACK-UNIT was expanded from a field length of 12 to 15, and the final 3 spaces were redefined as UNIT5 (field length = 2) and QUAL5 (field length = 1). MS was expanded from a field length of 16 to 20, and the 4 added spaces were redefined as MS5. Plotted the coverage after making these adjustments and spot verified to be sure the MS labels remained valid. The result of this processing was the coverage STACK4NEW3.
10-28-94 Corrected the fourth error (see 10-6-94 above) - which was adding one missing arc. CLEANED the coverage after this, creating the coverage STACK4NEW4.
In discussions with Don Keefer, decided to drop additional items from STACK4NEW4.PAT. These are:
PC-UNIT4 PA UT2 PC-UNIT18 PC4 UT3 UT UT1 UT4
Before dropping these items, copied STACK4NEW4 TO STACK4NEW5. Thus, the items can be recovered if necessary.
The reasoning for dropping these items is outlined in the following memo by Don Keefer.
(Begin Keefer memo: 10-28-94)
PC-UNIT18: This item contains 20 different values that represent map unit definitions from the map, "Potential for Contamination of Shallow Aquifers from Land Burial of Municipal Waste," by Berg and Kempton. The definitions are presented in a Survey Circular, Circ 532 (Berg, Kempton, and Cartwright). I generated a series of Info programs to interpret the items stack-unit, ut, and pa, and re- classify the polygon based on the definitions from Circ 532. I should note that there was a surprising amount of difficulty in getting these polygons accurately reclassified. This was due to a certain amount of overlap in several map-unit definitions. I found that I would get a different assignment of pc18 values, coverage wide, if I ran the programs in a different sequence. I was able to do a lot of cross checking for accuracy - since the reclassification was based on logical conditions, I was able to simply check the log on a subset of polygons, and used that to confirm that interpretations were made correctly. The long and the short of it are that, due to the difficulties involved in getting things to work perfectly, there is a small possibility that some polygons are mis-interpreted. Now that the stack map has been edited, these values need to be updated or deleted. I would recommend that this item is deleted from the updated version of the stack map, so that it won't be misinterpreted.
UT: This stands for unit type. It was a simple way of identifying the general lithology of each unit. I did take a perspective that was concerned more with relative hydraulic parameters that separation of distinguishable depositional environments. Accordingly, I lump units that I felt would have similar hydraulic characteristics.
PA: This item defines the unit number (from the surface down) that is the uppermost potential aquifer. I defined a potential aquifer a sand and gravel, fractured limestone, or uncemented sandstone that was continuous within the mapped unit. The stack map only identifies units that were 5 ft thick or continuous over 1 sq km, so these qualifiers are also added to the above definitions.
PC-UNIT4: This item was basically a generalization from pcunit18. I set this value using the pa and ut items. pcunit_4 is a classification of polygons based on 4 different depths to the uppermost aquifer (within 5 ft, 20 - 50 ft, and not within 50 ft) This item has been redefined to pc4, with only 1 character value in length. When I first made this generalization, I thought it might useful to add another space for within-group delineations. However I don't think I have ever used this. I have used this item a lot in more recent interpretive hydro maps (i.e. aquifer recharge, ag chemical maps)
Unfortunately, with the update of the stack-unit map, all of these item values are obsolete. I would recommend dropping these items from any final version. We can add them back in at a later date - when there is time to recalculate and check them.
(End Keefer memo)
The following occurred between 11/94 and 1/95: The county boundaries were updated with data from the ISGS database coverage illimap, and the four stack-unit plates were joined to form a state-wide coverage called stack-st.
Also, the state boundary has been updated with detailed data from the ISGS Illimap database. A notable result of this update was that parts of the northern and northeastern boundaries of the state were shifted south and west up to 1500 feet. This is due to (1) the original northern boundary on STACK1 being digitized as a straight line, while the updated boundary is the more accurate latitudinal arc segment; and (2) the coastline of the greater Chicago area being better represented on the updated boundary. Specifically, the boundaries were moved: approx. 300 ft. south at the NW and NE corners of the state, and approx. 1500 ft. south at the center point of the northern boundary, and; from 0 to approx. 1500 ft. west in the Chicago shoreline vicinity. Note that no rubbersheeting took place, so any inconsistencies introduced by this operation are strictly localized to the boundary areas.
2-17-95 Clark Co. area was updated with more recent data, on authority of Dick Berg.
3-27-95 Made approx. 30 label updates to coverage as requested by Dick Berg.
Revisions made to data:
Prior to the processing of 1994, no revision numbers had been assigned to this coverage. Thus, the original coverages will be arbitrarily assigned revision number 1 and this updated version will be revision number 2.
The features were imported into the ISGS SDE enterprise database following steps outlined in ISGS procedure GISDB_0009.
Person who carried out this activity:
, University of Illinois Web Privacy Notice.
, University Copyright Policy (stated in the General Rules Concerning University Organization and Procedure, Article III, Section 4).
, Policy on Appropriate Use of Computers and Network Systems at the University of Illinois at Urbana-Champaign.
Polygon attribute values were verified polygon by polygon against the source mylar separates by three separate individuals. The logical consistency of stack-unit designations was verified at the same time (i.e. Did sum of stacked thickness account for 50 feet of depth? Were geological units in the proper order?)
Horizontal positional accuracy was verified by at least three individuals by visual comparison (manual overlay) of source mylar separates and hard-copy plots. Arcs within one line-width of source mylars were deemed acceptable. For accuracy of source data, consult Berg and Kempton, 1988, ISGS Circular 542.
This feature class includes updates not on the published version. A small area (approx 1-2 square miles) north of Martinsville in Clark County was updated in 1996. The entire southern portion of the state that falls within the 1 x 2 degree Paducah quadrangle was updated from the Paducah stack-unit map in 1995.
Polygon and chain-node topology was present in the source coverage. This data set 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. There are no known arc or polygon attribute values outside the appropriate value domains.
Are there legal restrictions on access or use of the data?
- 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.
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, email@example.com. License fees and a license agreement may be required, depending on the proposed usage.
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.
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
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.
Illinois Natural Resources Geospatial Data ClearinghouseGenerated by mp version 2.8.25 on Thu Apr 02 09:54:12 2009