DESCRIPTION OF THE DIGITAL DATABASE FOR GEOLOGIC MAP OF IO USGS SCIENTIFIC INVESTIGATIONS MAP 3168 INTRODUCTION This digital database for the Geologic Map of Io (USGS SIM 3168) includes several GIS features that collectively present the entire content of the geologic map, along with supporting files and metadata. Data is in ArcGIS geodatabase format, including attribute domains, and is collated within a single feature dataset that preserves the relevant geographic information. Together with the geologic pamphlet, the GIS database provides georeferenced information on the geologic units, structure, and morphology of Io. All vector GIS data are in geographic coordinate system (GCS_Io_2000, radius of 1821460m) using decimal degrees for the horizontal units. Images are in a meter Cartesian plane using the various map projections as listed below. GEOLOGIC CONTENT This database contains one ArcGIS feature dataset with the following geologic content: Io_GeoContacts -- Final geologic contact polyline feature class. Contains a "TYPE" field denoting the type of geologic contact. Io_GeoUnits -- Final geologic unit polygon feature class. Contains a "AreaKm2" field containing the area of each polygon, as calculated using the spheroid. Contains a "Unit Name" field denoting the unit name. Contains a "Unit" field denoting the unit symbol. Graticules -- various reference graticule as polyline feature class. Io_Structure -- Final structural and morphologic polyline feature class. Contains a "TYPE" field denoting the type of linear feature. Io_LocationFeatures -- Final locational feature point feature class. Contains a "TYPE" field denoting the type of locational feature. Io_HotSpots_Locations -- hotspot locations, point feature class. Io_Mountains -- Io mountain locations, point feature class. Contains a "HeightKm" field denoting the height of the mountain in kilometers. The team developed the following five-step strategy for producing a new global map using the USGS mosaics (see Io SIM 3168 map text and Williams and others, 2007): Step 1. Map diffuse deposits separately using color data only (Color mosaic) Step 2. Map mountains, plateaus, and layered plains (Combined mosaic, supplemented w/low-sun images) Step 3. Map vents and paterae (Combined and Color mosaic) Step 4. Map lava flows. First map those around each vent, then add more detail within flucti (Combined and Color mosaic) Step 5. Map plains last (Combined and Color mosaic) Williams, D.A., L.P. Keszthelyi, D.A. Crown, W.L. Jaeger, and P.M. Schenk, 2007, Geologic mapping of the Amirani- Gish Bar region of Io--Implications for the global geologic mapping of Io: Icarus, v. 186, 204-217. BASE MAP CONTENT Four distinct image products were created by the USGS and were used in this mapping project: (1) a global mosaic of Galileo Solid State Imager (SSI) color images (hereafter referred to as "color mosaic"); (2) a global mosaic of the best resolution Galileo SSI monochrome images (hereafter referred to as "Galileo monochrome mosaic"); (3) a global mosaic of the best resolution Voyager Imaging Science Subsystem (ISS) and Galileo SSI monochrome images (hereafter referred to as "combined monochrome mosaic"); and (4) a merged product combining Galileo color information with the higher resolution combined monochrome mosaic (hereafter referred to as "merged mosaic.") There are important technical details to consider regarding the production of the new global Io mosaics. Each of these products is described more fully below. An extensive set of ancillary data was developed for each mosaic to help users understand the various combinations of data from different sensors, filters, dates, and illumination and viewing geometries. These include footprint plots showing the identity of each of the component images, and diagrams that show the incidence, emission, and phase angles, along with the spatial resolutions of the individual frames used. For more see Io SIM 3168 map text. These data are available for download at: http://astrogeology.usgs.gov/products/Io-Voyager- Galileo-Global-Mosaics DIGITAL DATABASE AND METADATA PACKAGE (Io_SIM3168_Database.zip) The geologic map files, basemap, and supportive files are included in the database package, as described below: File Description --------------------------------------------------------- sim3186_readme.txt This readme file. Sim3168_Io_metadata.txt Text-format FGDC-style metadata for the database package Sim3268_Io_metadata.xml XML-format FGDC-style metadata for the database package Io_Geology_SIM3168_Arcmap10.mxd ArcGIS version 10 project for the database package Io_Geology_SIM3168_Arcmap10.pmf ArcReader (free viewer) project for the database package "Metis_working" directory -------------------------------------------- Io_Geology_SIM3168.gdb ArcGIS geodatabase containing all digital geologic map information Io_Geology_SIM3168_shapefiles directory ESRI shapefile format for the geologic files above layerSymbology directory ArcGIS layer files containing symbol look-up tables for ArcMap projections directory Definitions for the various projections use during mapping vector_misc directory Graticule shapefiles for the projections used during mapping "raster_baseMaps" directory -------------------------------------------- Please see SIM 3168 text for description of base maps used in mapping. All files are saved in a GeoTiff format using the projections as listed below: * Mercator, center lon = 180 o Io_SSI_VGR_bw_merc180.tif (combined mosaic) o Io_SSI_VGR_color_merge_merc180.tif (merged mosaic) * North Polar Stereographic, center lon = 0, center lat = 90 o Io_SSI_VGR_bw_npole.tif (combined mosaic) o Io_SSI_VGR_color_merge_npole.tif (merged mosaic) * South Polar Stereographic, center lon = 0, center lat = -90 o Io_SSI_VGR_bw_spole.tif (combined mosaic) o Io_SSI_VGR_color_merge_spole.tif (merged mosaic) * Simple Cylindrical, center lon = 180 o Io_SSI_VGR_bw_Equi_Clon180_8bit (combined mosaic) o Io_color_merged_clon180.tif (merged mosaic) Users of the database package may wish to download the SIM 3168 pamphlet for the contained Description of Map Units. The material described above is available on the World Wide Web at http:/pubs.usgs.gov/sim/ 3168/ 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 ArcGIS v 9.3, a commercial Geographic Information System produced by Environmental Systems Research Institute (ESRI), Redlands, California. Data layers are also made available in ESRI shapefile format which is usable in nearly all GIS applications. OBTAINING HARD-COPY OF SIM-3168 USGS Information Services Box 25286 Denver Federal Center Denver, CO 80225-0046 (303) 202-4200 1-888-ASK-USGS Email: infoservices@usgs.gov ACKOWLEDGMENTS The authors would like to thank Tracy K.P. Gregg and Rosaly M.C. Lopes for their reviews that improved the quality of this map. The authors would like to thank Trent Hare, Rose Hayward, Ken Tanaka, and the staff of the U.S. Geological Survey's Astrogeology Science Center for their assistance in producing the basemap products and for editing and support using ArcGIS(TM) software for producing this map. The authors would like to acknowledge all of the engineers, scientists, and managers who helped bring NASA's Voyager and Galileo missions to fruition, without which we would not have had the data to produce this map.