David V. Smith Robert R. McDougal 2007 1.0 vector digital data Digital Data for Scientific Investigations Report 2007-5191 sir2007_xxx_intrusives_edwards Denver, Colorado U.S. Geological Survey http://pubs.usgs.gov/sir/2007/5191/ David V. Smith Robert R. McDougal Unpublished Material Unknown document Scientific Investigations Report 2007-5191 Denver, Colorado U.S. Geological Survey http://pubs.usgs.gov/sir/2007/5191/ The outlines of igneous rock occurance were produced from the 2001 aeromagnetic data by separating shallow equivalent sources using matched bandpass filtering with layer depth of 264 meters. The shallow source layer was processed to obtain a horizontal gradient grid, which was contoured using a threshold set by interpretive modeling of isolated, discrete anomalies. Closed contours corresponding to validated anomalies were included in the final transparancy layer. The distribution and aereal extent of igneous rocks in the Edwards aquifer are of interest in understanding the influence of igneous intrusive rocks on the limestone aquifer at regional and local scales. 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 readme files for completeness and accuracy. 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. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. 2007 publication date Complete None planned -100.028693 -98.814996 29.623855 29.208850 American Geological Institute Glossary of Geology Airborne magnetic data Igneous intrusives Aeromagnetic data Magnetic anomalies Edwards aquifer Geographic Names Information System (GNIS) Texas Uvalde County Medina County Bexar County none none David V. Smith U.S. Geological Survey Geophysicist mailing and physical address

Denver Federal Center, MS973, bldg. 20

Denver Colorado 80225 USA 303-236-1228 303-236-1425 dvsmith@usgs.gov Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 2; ESRI ArcCatalog 9.2.2.1350 Attributes vaules were calculated using a GIS and are considered accurate. In addition, attributes were checked and evaluated as part of the review process associated with the publication of the source report. Lines forming polygons join at endpoints to completely enclose defined areas. No duplicate polygon features or pseudo nodes exist. Nodes are represented by a single coordinate pair that indicates the starting and (or) ending point of the line forming the polygon. All vertices that define the shapes of the polygons are represented by unique coordinate pairs. Digitized all of aeromag map. 100% complete. The accuracy of the compiled digital line features in the data set is based upon the accuracy of source maps and digital data sets which generally are compiled to meet National Map Accuracy Standards. Horizontal positional accuracy was tested by visually comparing these line features to source maps using a GIS and hardcopy plots. Miggins, Daniel P. Blome, Charles D. Smith, David V. 2004 document Open-File Report 2004-1031 Denver, Colorado U.S. Geological Survey Figure 2 (B) http://pubs.er.usgs.gov/usgspubs/ofr/ofr20041031 250000 paper 2004 publication date Smith and others, 2004 Source map The final interpretive map was produced by creating two overlapping GIS layers. First, the contours identified as shallow igneous bodies were digitized as polygons and attributed as to geographic location and area using the software package ERDAS Imagine v. 8.6 (Leica Geosystems LLC). The GIS coverage was topologically "built" and saved as an ARC coverage (ARC interchange format) and shapefile. Next, the topographic base map was created by mosaicking two U.S.G.S. 1:250,000 scale contour maps of San Antonio and Del Rio, Texas (UTM zone 14, North American Datum 1927). The digital mosaic was georeferenced using fifty control points evenly distributed throughout the image and a second order polynomial warp method. Finally, the coverage of igneous intrusions was adjusted to a transparency of fifty percent and overlaid on the georeferenced digital base map. Smith and others, 2004 2007 Robert R. McDougal U.S. Geological Survey Geologist mailing and physical address

Denver Federal Center, MS964D, bldg. 20

Denver Colorado 80225 USA 303-236-1854 303-236-3200 rmcdouga@usgs.gov Vector G-polygon 390 Universal Transverse Mercator 14 0.999600 -99.000000 0.000000 500000.000000 0.000000 coordinate pair 100 100 meters North American Datum of 1927 Clarke 1866 6378206.400000 294.978698 Aeromagnetic anomalies Aeromag anomalies interpreted as Igneous Intrusions for the Edwards Aquifer Metadata author FID Internal feature number. Environmental Systems Research Institute, Inc. (ESRI) Sequential unique whole numbers that are automatically generated. Shape Feature geometry. ESRI Coordinates defining the features. AREA Area of intrusive (in meters squared) Metadata author 21610.59 9128956.5 Meters PERIMETER Perimeter of intrusive (in meters) metadata author 596.96 29619.77 meters U.S. Geological Survey physical address

Denver Federal Center

Denver Colorado 80225 USA 1-888-275-8747 <http://ask.usgs.gov/> Downloadable Data Although these data have been processed successfully on a computer system at the U.S. Geological Survey, no warranty expressed or implied is made regarding the accuracy or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. This disclaimer applies both to individual use of the data and aggregate use with other data. These data should be directly acquired from a U.S. Geological Survey server, and not indirectly through other sources that may have altered the data in some way. Shapefile ARC Version 9.x no compression applied 0.128 http://pubs.usgs.gov/sir/2007/5191/ none 20070607 Robert R. McDougal U.S. Geological Survey Geologist mailing and physical address

Denver Federal Center

MS964D

bldg. 20

Denver Colorado 80225 USA 303-236-1854 303-236-3200 rmcdouga@usgs.gov FGDC Content Standards for Digital Geospatial Metadata FGDC-STD-001-1998 local time none Acknowledgement of the U.S. Geological Survey would be appreciated in products derived from these data. 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 Federal Geographic Data Committee-compliant metadata file is intended to document the data set in nonproprietary form, as well as in ArcGIS format, this metadata file may include some ArcGIS-specific terminology. http://www.esri.com/metadata/esriprof80.html ESRI Metadata Profile