DESCRIPTION OF THE DIGITAL DATABASE FOR Geologic Map of the Lada Terra Quadrangle (V56), Venus USGS SCIENTIFIC INVESTIGATIONS MAP 3249 Reference: Kumar, P.S., and Head, J.W., 2013, Geologic map of the Lada Terra quadrangle (V56), Venus: U.S. Geological Survey Scientific Investigations Map 3249, scale 1:5,000,000, available at http://pubs.usgs.gov/sim/3249/ . INTRODUCTION This publication provides a geological map of Lada Terra quadrangle (V56), a portion of the southern hemisphere of Venus that extends from lat 50° S. to 70° S. and from long 0° E. to 60° E. The geological map of V56 quadrangle reveals evidence for tectonic, volcanic, and impact processes in Lada Terra in the form of tesserae, regional extensional belts, coronae, and volcanic plains. In addition, the map also shows relative age relations such as overlapping or cross-cutting relations between the mapped geologic units. V56 is bordered by Kaiwan Fluctus (V44) (Bridges and McGill, 2002) and Agnesi (V45) quadrangles in the north and by Mylitta Fluctus (V61) (Ivanov and Head, 2006), Fredegonde (V57) (Ivanov and Head, 2010a), and Hurston (V62) quadrangles in the west, east, and south, respectively. For more, see pamphlet for SIM 3249. All GIS data are in Lambert Conformal Conic projection using the Venus 1985 geographic coordinate system (GCS_Venus_1985). Units are in meters. GEOLOGIC CONTENT (contents of "ESRI_FileGeodatabase" Folder, V56_Geology.gdb) This ArcGIS geodatabase contains one feature dataset (V56_Geology_FD) with the following features: Geologic_Contacts_V56 - Line feature class, geologic unit and map boundaries including symbol types: Approximate, certain, gradational. Shields_V56 - Point feature class, center point locations of sheilds. Geologic_Units_V56 - Polygon feature class, geologic unit polygon feature class. Contains a "Type" field denoting the unit symbol. Structure_V56 - Line feature class, denoting structural features. BASE MAP CONTENT The orbiting phase of the Magellan mission extended from August 10, 1990, to October 12, 1994. During mission cycles 1, 2, and 3 from September 1990 to September 1992, the spacecraft collected synthetic aperture radar (SAR) images, passive microwave thermal emissions, and measurements of backscatter power at small angle of incidence, covering ~98 percent of the surface of Venus. During mission cycles 4, 5, and 6 from September 1992 and October 1994, high-resolution gravity measurements were made. The SAR instrument operated at a wavelength of 12.6 cm (S-band) with horizontal transmit/receive polarization that allowed cloud penetration and discrimination of wavelength-scale surface roughness. The catalogue of SAR image data and image interpretation methods are provided by Wall and others (1995) and Ford and others (1993), respectively, in addition to compilations made by various other researchers. For more, see pamphlet for SIM 3249. DIGITAL DATABASE AND METADATA PACKAGE (SIM3249_database.zip) The geologic map files, basemaps, and supportive files are included in the database package, as described below: "SIM3249_V56_GIS" directory -------------------------------------------- Files Description --------------------------------------------------------------------- --------------------------------------------------------------------- SIM3249_README.txt This readme file. SIM3249_V56_metadata.txt Text-format FGDC-style metadata for the database package SIM3249_V56_metadata.xml XML-format FGDC-style metadata for the database package SIM_3249_V56_ArcMap10.1.mxd ArcGIS (version 10.1) project for the database package "Raster" base map directory -------------------------------------------- v56_r_l_lambc.jp2 - Magellan F-Map SAR mosaic produced by USGS in Geojpeg2000 format Magellan_colorizeTopo_dd0_6600m.jp2 - Magellan F-Map SAR mosaic colorized by topography produced by USGS Magellan_C3-Midr_dd0_2km_stretched_lambertConf.jp2 - Magellan C3-SAR mosaic produced by USGS "radar_props" Magellan Global Topography, Emissivity, Reflectivity, and Slope Data Record (GXDR) http://pds-geosciences.wustl.edu/missions/magellan/gxdr/index.htm "ESRI_*" directories -------------------------------------------- "V56_Geology.gdb" - ArcMap 9.3 versioned geodatabase "Shapefiles" - This directory contains GIS shapefiles exported from the ArcGIS geodatabase described above. As such, the names and descriptions for each shapefile are identical to the content of the included geodatabase. See above "GEOLOGIC CONTENT" for details. Users of the database package may wish to download the PDF version of the map for the Description of Map Units. The material described above is available on the World Wide Web at http:/pubs.usgs.gov/sim/3249/ ZIP FILES The files described above are packaged within a ZIP file. Utilities to uncompress ZIP files are available for most operating systems and may be found readily with a simple web search. DIGITAL DATABASE FORMAT The digital information compiled in this report used v 9.3, a commercial Geographic Information System produced by Environmental Systems Research Institute, Redlands, California. OBTAINING HARD-COPY OF SIM 3249 USGS Information Services Box 25286 Denver Federal Center Denver, CO 80225-0046 (303) 202-4200 1-888-ASK-USGS Email: infoservices@usgs.gov