Clawges, Rick Price, Curtis 1999 1.0 map Open-File Report 99-77 Reston, VA U.S. Geological Survey http://water.usgs.gov/lookup/getspatial?ofr99-77_aquif75m This digital data set describes productive aquifers in the conterminous United States. The data set was generated from a U.S. Geological Survey 1:7,500,000-scale map of productive aquifers of the conterminous United States. This data set is a generalized representation of productive aquifers in the conterminous United States and was created for use in the analysis of ground-water quality data on volatile organic compounds (VOCs) by the U.S. Geological Survey (USGS) National Water-Quality Assessment Program (NAWQA) VOC National Synthesis Team. The source map for this data set is on p. 122-123 of the U.S. Geological Survey National Atlas (U.S. Geological Survey, 1970) Coastlines and political boundaries are modified from a digital version of U.S. Geological Survey 1:2,000,000 county boundaries (USGS, 1984). REVIEWS This electronic report was subjected to the same review standard that applies to all U.S. Geological Survey reports. Reviewers were asked to check the topological consistency, tolerances, attribute frequencies and statistics, projection, and geographic extent. The reviewers checked the metadata and a_readme.1st files for completeness and accuracy. REFERENCES Environmental Systems Research Institute, Inc. (ESRI), 1997, Arc/INFO 7.1.1 Help, Redlands, California, [on-line documentation]. Lanfear, K.J., 1984, Digital map of counties and county equivalents in the conterminous United States: U.S. Geological Survey data available on the World Wide Web, accessed July 21, 1998, at URL http://water.usgs.gov/lookup/getspatial?county2m U.S. Geological Survey, 1970, The National Atlas of the United States of America, Washington, D.C., U.S. Government Printing Office, 417 p. NOTES Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. 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. Although this Federal Geographic Data Committee-compliant metadata file is intended to document the data set in nonproprietary form, as well as in ARC/INFO format, this metadata file may include some ARC/INFO-specific terminology. 1965 The data is based on the map from U.S. Geological Survey (1970), which was compiled in 1965. Complete None planned. -127.84205584 -65.40873623 48.1924194 22.87753347 None aquifer inlandWaters None Conterminous 48 United States None None Curtis V. Price U.S. Geological Survey Physical Scientist mailing address

1608 Mountain View Rd

Rapid City South Dakota 57702 United States of America 1-888-275-8747 (605) 355-4523 cprice@usgs.gov Contact via email Compilation of the data sets was supported by the National Water-Quality Assessment (NAWQA) Program of the U.S. Geological Survey. The objectives of the NAWQA Program are to: (1) describe current water-quality conditions for a large part of the Nation's freshwater streams, rivers, and aquifers, (2) describe how water quality is changing over time, and (3) improve the understanding of the primary natural and anthropogenic factors that affect water-quality conditions. National analysis of data, based on aggregation of comparable information obtained from across the United States, is a major component of the NAWQA Program. These data sets were created in support of NAWQA national data analysis activities. Public Unclassified None Operating System: dgux, 5.4R3.10, AviioN UNIX, ARC/INFO version 7.1.1 Polygon and chain-node topology present. This data set includes all productive aquifer boundaries presented on p. 122-123 of National Atlas of the United States (U.S. Geological Survey, 1970). No tests performed, except a visual check to see how well the data set lines corresponded to those on the paper map. No tests performed, except a visual check to see how well the data set lines corresponded to those on the paper map. U.S. Geological Survey 1970 map Washington, D.C. U.S. Geological Survey 7500000 mylar 1970 publication date none none Lanfear, K.J. 19840816 map Reston, Virginia, USA U.S. Geological Survey http://water.usgs.gov/lookup/getspatial?ofr99-77_aquif75m online 19840816 as of 1983 county2m US boundary and coastlines Original source material was a mylar separate of aquifer boundaries and tics provided by James Witmer of the U.S. Geological Survey in Reston, Virginia. The mylar separate then was scanned to create a two-color tiff file at the U.S. Geological Survey GIS laboratory in Denver, Colorado. Details of the scanning procedure follow: >Arcscan Version 7.2 - 16-Dec-1992 V6000(SCSI) >output file = aquifers.tif >creation date = 25-Jan-96 11:31:06 >density = 400 pixels / inch >x (in) = 1.000 27.000 >y (in) = 3.000 20.000 >output file x pixel limits = 1 10400 >output file y pixel limits = 1 6800 >speed = 100 % >output file size = 8840512 bytes >scan time = 107 seconds >sensitivity = 150 10 0 >min width = 0.000 >bi-level compression type 1 (uncompressed) ARC/INFO software and commands (ESRI, 1997) were then used to convert the image file to a coverage. ARC/INFO commands and modules are shown below in capitals. Step 1. Convert image to a grid using IMAGEGRID command. Step 2. Convert from raster to vector using GRIDLINE command and the following tolerances: thickness = .018, dangle = .01, and weed = .002. Step 3. Set tolerances for the coverage to the following: fuzzy = .002, dangle = .002, nodesnap = .01, weed = .002, and tic_match = .005. Step 4. Remove extraneous arcs from coverage including tic marks and legend lines from scanned image. Step 5. Transform coverage to Albers coordinates: >Scale (X,Y) = (190577.230,190633.270) Skew (degrees) = (-0.008) >Rotation (degrees)=(-0.270) Translation=(-2421628.155,3391460.203) >RMS Error (input,output)=(0.004,809.288) > >Affine X = Ax + By + C > Y = Dx + Ey + F >A = 190575.106 B = 874.074 C = -2421628.155 >D = -899.686 E = 190631.267 F = 3391460.203 >tic id input x input y > output x output y x error y error >------ ------------- ----------- ----------- ---------- > 1 1.476 -9.394 > -2149444.042 1599617.327 847.794 -203.129 > 2 5.485 -1.314 > -1376570.737 3135813.678 -984.617 235.911 > 3 20.687 -1.084 > 1519221.684 3166286.216 692.900 -166.017 > 4 18.316 -13.346 > 1057865.943 830635.046 -556.077 133.235 Step 6. Added United States boundary using coverage /home/vocgis/lib/pol/stategen, which is a generalized version of county2m coverage. (The linework is unmodified except for certain coastline areas such as Louisiana, which have been generalized and smoothed.) Step 7. Clean up intersect errors and dangles. Step 8. Build topology. Step 9. Create labels and rebuild. Step 10. Assign attribute data to polygons. 19960506 Step 11. Used UNSPLIT in Arcedit to remove unnecessary pseudo nodes. Step 12. Rebuild topolgy Step 13. Copied coverage from DOUBLE to SINGLE precision and CLEANed. Used fuzzy tolerance of 0.920 and dangle length of 0.002. Step 14. Used RENODE to sequentially number nodes. 19981028 Vector Point 2966 String 5409 GT-polygon composed of chains 2967 Albers Conical Equal Area 29.5 45.5 -96 23 0.00000 0.00000 coordinate pair 0.92 0.92 Meters North American Datum of 1927 Clarke 1866 6378206.4 294.98 There is a polygon attribute table associated with this file: >AQUIF75M.PAT: > >COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC Notes > 1 AREA 8 18 F 5 > 9 PERIMETER 8 18 F 5 > 17 AQUIF75M# 4 5 B - > 21 AQUIF75M-ID 4 5 B - > 25 AQCODE 2 2 I - > 27 SYMBOL 4 5 B - > 31 DESC 60 60 C - AREA is the area of the polygon in square meters PERIMETER is the perimeter of the polygon in meters AQUIF75M# is a program-generated feature identity number AQUIF75M-ID is a user-assigned feature identity number AQCODE is an assigned integer aquifer number ranging from 1 to 12 SYMBOL is an assigned number for shading symbol that can be used with the SHADESET COLORNAMES and the POLYGONSHADES command in ARC/INFO's ARCPLOT module. DESC is the name of the aquifer from U.S. Geological Survey National Atlas (1970). All unique combinations values of these items are listed below: >AQCODE SYMBOL DESC > > 1 0 No aquifer mapped > 2 46 Unconsolidated watercourse > 3 17 Unconsolidated sand and gravel > 4 107 Consolidated sandstone > 5 71 Consolidated carbonate > 6 86 Consolidated sandstone/carbonate > 7 120 Consolidated volcanic > 8 114 Consolidated crystalline > 9 12 Consolidated sandstone under sand and gravel >10 67 Consolidated carbonate under sand and gravel >11 85 Consolidated sandstone/carbonate under sand and gravel >12 23 Consolidated volcanic underlies sand and gravel None 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. Export Full coverage zipped 1 http://water.usgs.gov/GIS/dsdl/ofr99-77_aquif75m.e00.gz DLG Full coverage zipped 1 http://water.usgs.gov/GIS/dsdl/ofr99-77_aquif75m.dlg.tgz SDTS Full coverage zipped 1 http://water.usgs.gov/GIS/dsdl/ofr99-77_aquif75m.sdts.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+ofr99-77_aquif75m FGDC Content Standards for Digital Geospatial Metadata FGDC-STD-001-1998