NATURAL RESOURCES GEOGRAPHIC INFORMATION SYSTEM COVERAGE DOCUMENTATION COVERAGE NAME: COALIDS DOCUMENTATION REVISION: 2/19/93 DESCRIPTIVE NAME: Identifiers for surface and underground mines STATUS: Complete DESCRIPTION: Point coverage file used to link mine names to mines in coal mine polygon coverage. This was created so that one identifier could be used for each mine. GEOGRAPHIC EXTENT: Thirty-eight counties in southeastern and southcentral Iowa COVERAGE TYPE: Points COVERAGE SIZE: Arcs: 0 Polygons: 0 Labels: 3,062 Tics: 167 Annotations: 0 File size: 672 Kbytes MAP PROJECTION: Universal Transverse Mercator (UTM), Zone 15 MAP UNITS: Meters DATUM: NAD27 SOFTWARE/VERSION: PC ARC/INFO 3.4D COVERAGE CREATED: 3/91 COVERAGE DEVELOPER: Mary R. Howes, Joost A. Korpel, Madhukar Mohan MODIFICATIONS: Mary R. Howes DNR CONTACT: Mary R. Howes, Iowa Department of Natural Resources, Geological Survey Bureau, 123 North Capitol, Iowa City, Iowa 52242, 319/335-1575 ORIGINAL SOURCE INFORMATION: Media: Varies; blueprint, oil cloth, microfilm Title: Varies Author/Agency: Varies Published Date: Varies Compiled Date: Varies Scale: Varies, most common are 1"=100' and 1"=200' Projection: None Geographic Control: Latitude and Longitude at corners of U.S. Geological Survey 7.5' quadrangle maps. Data conversion: Mines were digitized with AutoCAD and converted to DXF format for importation to pcARC/INFO. All quadrangles were transformed to their respective projections and finally projected to UTM coordinates and joined. References: Coalmine database ACCURACY ASSESSMENT: Original sources vary greatly in accuracy from very accurate engineers' surveyed maps to generalized outlines on highway department maps to point locations in file data or published reports. Accuracies for the mines (not the points in this coverage) are indicated by entries in the MINE_TYPE field. The following discussion is drawn from the ACCURACY ASSESSMENT section of the documentation for MINES. Accuracy of the data for the mines has two components: 1)accuracy of the mines location (positional accurancy), 2) accuracy of the area defined by the polygon (areal accuracy). MAP: These mines are digitized from photographs of surveyed maps that has either two recoverable location points or one point and a scale and a directional arrow. The smallest scale photograph used was approximately 1:15,000. The mines were geographically referenced to 7.5' quadrangle maps. Thus, the positional accuracy is approxi- mately 48 meters and the areal accurancy is approximately 45 meters. SMAP: These mines were digitized from photographs of surveyed maps which lack recoverable location points. They were locatable to one PLSS section of less from a verbal description. These were digitized using the same techniques as the MAP mine types, but they were located at the center of the given location. The areal accuracy is approximately 45 meters. The positional accuracy is 1600 meters. NOMAP: These are unmapped underground mines digitized from outlines on 7.5' quadrangle maps that were transferred from hand-drawn outlines on highway commission maps (approx. 1:20,000) using a grid. The areal accuracy of these maps is known to be quite variable based on compari- sons to existing surveyed mine maps, but the positional accurancy is generally good. The areal accuracy is estimated to by 400 meters and the positional accuracy is 50 meters. SURFACE: The surface mines were digitized from 7.5' quadrangle maps. The 7.5' quadrangles are the smallest-scale source and probably re- present the limit of accuracy. Areal and positional accuracy are estimated to be 48 meters. QMINE, SMINE: These mines are known as point locations only. Buffers with an area of one acre are used in MINES to satisfy the software requirements. The points were plotted on 7.5' quadrangle maps which were the source for digitizing. Areal accuracy cannot be estimated. Positional accuracy is estimated based on the precision of the location. QMINE signifies a point which can be located to 1/4 PLSS section or less and SMINE was used for mines which could be located to one PLSS section or those for which the source gave a distance and direction. The positional accuracies of the points are estimated to be 800 and 1600 meters, respectively. ASSOCIATED COVERAGES: MINES: arc and polygon coverage of mines ENTRANCE: point file of shaft and/or slope entrances for each site where this information is available ASSOCIATED FILES: MINENAME: (in MINES coverage) name and site identifier for each mine COALMINE: coal mine database, related by site identifier to COALIDS COMMENTS: This coverage was constructed to provide a single identifying point for each mine. It is used for the purpose of queries and plotting. ARC ATTRIBUTE FILE ITEMS (AAT): None POLYGON ATTRIBUTE FILE ITEMS (PAT): None POINT ATTRIBUTE FILE ITEMS (PAT): None AREA: Not used PERIMETER: Not used COALIDS_: Internal point identifier assigned by software. COALIDS_ID: User-assigned point identifer SITE_ID: Used to link MINENAME and COALMINE files to points SITE_ID1: Site identifier for uppermost level of mining or for single level, consists of county number x 10,000 + site identifier from COALMINE database, used for verification purposes with MINES SITE_ID2: Site identifier for second level of mining (if needed), otherwise 0 SITE_ID3: Site identifier for third level (if needed), otherwise 0 MINE_TYPE: mine type MAP: surveyed mine map with good location, uppermost level, used where only one level present NOMAP: mine with known extent from source other than surveyed map SMAP: surveyed mine map with poor location SURFACE: surface mines digitized directly from 7.5' maps QMINE: mines with unknown extent, plotted as one acre buffer polygons around point location. Location known to within 1/4 sec. SMINE: same as QMINE, location known to within one sec. NUMBER: county number NAME: county name ANNOTATIONS: None TICS: Tics are placed at the corners of each county ****NOTICE**** This digital, geographically referenced data set was developed by the Iowa Department of Natural Resources to carry out agency responsibilities related to management, protection, and development of Iowa's natural resources. It resides in the Natural Resources Geographic Information System library. Although efforts have been made to make it useful to the Department, the Department assumes no responsibility for errors in the information. Similarly the Department assumes no responsibility for the consequences of inappropriate uses or interpretations of the data made by anyone to whom this data has been made available. The Department bears no responsibility to inform users of any changes made to this data. Anyone using this data is advised that precision implied by the coverage may far exceed actual precision. Comments on this data are invited and the Department would appreciate that documented errors be brought to staff attention.