Sharon Rafferty 19980630 (Version 1.0, July 08, 1998) Map Denver, CO U.S. Geological Survey, WRD http://water.usgs.gov/lookup/getspatial?co_wells_ha742 This digital geospatial data set consists of locations of coal, oil, gas and water wells shown as data points in the report, "Structure, Outcrop, and Subcrop of the Bedrock Aquifers Along the Western Margin of the Denver Basin, Colorado" (Robson and others, 1998). This data set was created to display well locations shown in Robson and others (1998). Procedures_Used: Well sites and tic marks were scanned from 1:50,000 maps (Robson and others, 1998) at 200 to 800 dots per inch, into a tagged image file format (TIFF, a bit-mapped file format). The TIFF's were converted to unrectified grids, ARC/INFO raster geospatial data sets by the ARC/INFO command IMAGEGRID. Vector geospatial data sets, known as coverages, in ARC/INFO-specific terminology, were created from ascii files contain- ing the latitude/longitude coordinates in degrees, minutes and seconds. These coverages were projected into a State Plane projection that was specific to each county map. From these coverages, link files were then created to help register the grids to the coverages by use of the ARC/INFO command CONTROLPOINTS. Arc: controlpoints fig2_grid fig2_lin fig2_tics nominal identity # point Registration root mean square errors of 0.005 or less were acceptable for the creation of link files. The unrectified grids were georectified with the ARC/INFO command GRIDWARP, which transforms or rubber sheets a grid along a set of links by using a first-order polynomial transformation. Polygon coverages were created from the grids with the ARC/INFO command GRIDPOLY. The labels were added to the polygons with the ARC/INFO command CENTROIDLABELS. An empty coverage was created in ARC with the bnd from the polygon coverage and brought into ARCEDIT with an edit feature of point. The GET command was used to bring in the labels from the polygon coverage. The coverage then was saved in ARCEDIT and built as a point cover. Arc: gridpoly fig2_rgrid fig2_cov Arc: createlabels fig2_cov Arc: centroidlabels fig2_cov inside Arc: create new_cov fig2_cov Arcedit: ec new_cov Arcedit: ef point Arcedit: get fig2_cov Arcedit: save new_cov Arc: build new_cov point The point coverage was attributed with the items TYPE and SITEID. The coverage was reopened in ARCEDIT and label points were assigned site numbers and codes for well type. Drafts of these coverages were plotted at a scale of 1:50,000, checked against the original sheets and corrected for omissions. The coverages were appended into a single coverage that was built. The final coverage was projected from State Plane to UTM. This data set is one of seven digital map data sets being published together for this area. The other six data sets are: ARAPBASE - structure contours on base of upper Arapahoe aquifer LFHTOP - structure contours on top of Laramie-Fox Hills aquifer LFHBASE - structure contours on bottom of Laramie-Fox Hills and Arapahoe aquifers GEO - geohydrologic unit boundaries GEOSYMB - point and line geologic structure information STUDYAREA - outline of studyarea The final coverage represents one thematic layer in maps in Robson and others (1998). The following is an AML to generate a graphic of this coverage. >display 9999 >killmap wells.map >map wells.map >mape studyarea >mapunits feet >pagesize 37 51 >mappos cen cen >clearsel >box 1.0 1.0 35 49.5 >arcs studyarea >/*THIS IS WHERE THE WELLS ARE PLOTTED >clearsel >resel wells point type = 1 >markerset water.mrk >markersymbol 108 >markersize .13 >markerpen .01 >markerput 108 >points wells >clearsel >resel wells point type = 2 >/*open circle with heavy line around it >markersymbol 109 >markersize .13 >markerpen .02 >markerput 109 >points wells >clearsel >resel wells point type = 3 >/*open circle >markersymbol 109 >markersize .13 >markerpen .01 >markerput 109 >points wells Reviews_Applied_to_Data: March 1998: Colleague review of 1:50,000-scale maps that were generated from the original data set. Manuscript review included validation of method as outlined in map report and inspection for positional accuracy. March 1998: Inspection of copy generated from this data set. April 1998: Colleague review of original digital data set and associated metadata. Metadata review included verification of table and column/item identities and definitions, validation of the reference data sets and citations, verification of consistency between log file and documented procedures, and validation of development method as described in the documentation. References_Cited: Robson, S.G., Van Slyke, George, and Graham, Glenn, 1998, Structure, outcrop, and subcrop of the bedrock aquifers along the western margin of the Denver Basin, Colorado: U.S. Geological Survey Hydrologic Investigations Atlas HA-742, 5 sheets, scale 1:50,000. Available through the internet at <URL:http://rockyweb.cr.usgs.gov/frontrange/> 1998 Current as of publication date. Complete None Planned -105.25683628 -104.58906752 40.88667734 39.2254652 none wells geophysical logs inlandWaters none Colorado, Front Range none These data are not to be used at scales greater than 1:50,000. William Horak U.S. Geological Survey Water Resources Division mailing address

Box 25046, MS 415, Denver Federal Center

Lakewood CO 80225 USA 1-888-275-8747 303-236-2904 (wfhorak@usgs.gov) http://water.usgs.gov/GIS/browse/wells.jpg Illustration of the dataset. jpg U.S. Geological Survey dgux, 5.4R3.10, AViiON UNIX ARC/INFO version 7.0.4 Well locations are based on location descriptions provided by well owner or operator to the Colorado Oil and Gas Conservation Commission or the Colorado Division of Water Resources. Point features present. See supplemental information. Scanned well locations generally are within 0.01 inch of original line work. U.S. Geological Survey 1998 Map Hydrologic Investigations Atlas HA-742 Denver, CO USGS, WRD mylar sheets 1997 1998 HA-742 Robson and others (1998) See Supplemental Information 1998 Point Point 1677 Universal Transverse Mercator 13 implied implied implied implied implied coordinate pair 18.4335230657 18.4335230657 Meters North American Datum of 1983 GRS1980 6378206.4 294.98 WELLS.PAT Attribute table of WELLS GIS software AREA Area of polygon in coverage units (meters) Computed Positive real numbers n/a GIS software PERIMETER Perimeter of polygon in coverage units (meters) Computed Positive real numbers n/a GIS software PERIMETER Perimeter of polygon in coverage units (meters) Computed Positive real numbers n/a GIS software WELLS# Internal feature number Computed Sequential unique positive integer n/a GIS software WELLS-ID User-assigned feature number User-defined Integer n/a GIS software TYPE Assigned code for well type see (Robson and others, 1998) 1,2,3 see Entity and Attribute Overview User assigned SITEID Identification number for wells see (Robson and others, 1998) alphanumeric see Entity and Attribute Overview User assigned Item TYPE is an identifier for the type of wells represented. Well numbers represent the following: 1 represents wells with geophysical logs that extend upward at least to the base of the Laramie-Fox Hills aquifer 2 represents wells with geophysical logs that do not extend upward to the base of the Laramie-Fox Hills aquifer. Altitude of base of aquifer was inferred by correlation to marker beds in upper part of Pierre Shale 3 represents wells where inferred base of Laramie-Fox Hills aquifer is above land surface Item SITEID is a number assigned by project personnel to identify the well label. > >WELLS.PAT: > >COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME > 1 AREA 8 18 F 5 > 9 PERIMETER 8 18 F 5 > 17 WELLS# 4 5 B - > 21 WELLS-ID 4 5 B - > 25 TYPE 3 3 I - > 28 SITEID 7 7 C - > > Not available U.S. Geological Survey Ask USGS - Water Webserver Team mailing

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Reston VA 20192 1-888-275-8747 (1-888-ASK-USGS) http://water.usgs.gov/user_feedback_form.html Although this data set has been used by the U.S. Geological Survey, U.S. Department of the Interior, no warranty expressed or implied is made by the U.S. Geological Survey as to the accuracy of the data and related materials. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the U.S. Geological Survey in the use of this data, software, or related materials. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. shape file Full coverage zipped 1 http://water.usgs.gov/GIS/dsdl/wells_shp.zip Export Full coverage zipped 1 http://water.usgs.gov/GIS/dsdl/wells.e00.gz Other Full coverage zipped 1 http://water.usgs.gov/GIS/dsdl/wells.tgz None. This dataset is provided by USGS as a public service. 20041108 U.S. Geological Survey Ask USGS -- Water Webserver Team mailing

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Reston VA 20192 1-888-275-8747 (1-888-ASK-USGS) http://answers.usgs.gov/cgi-bin/gsanswers?pemail=h2oteam&subject=GIS+Dataset+co_wells_ha742 FGDC Content Standards for Digital Geospatial Metadata FGDC-STD-001-1998