DESCRIPTION OF THE DIGITAL DATABASE FOR 
GEOLOGIC MAP OF THE METIS MONS QUADRANGLE (V-6), VENUS
U.S. GEOLOGICAL SURVEY SCIENTIFIC INVESTIGATIONS MAP 3158

INTRODUCTION

This digital database for the Geologic Map of the Metis 
Mons Quadrangle (V-6), Venus 
(http://pubs.usgs.gov/sim/3158/) 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 the V-6 quadrangle.  

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

This database contains one ArcGIS feature dataset with the 
following geologic content:

GeoContacts - Final geologic contact polyline feature 
class. Contains a "TYPE" field denoting the type of 
geologic contact.

GeoUnits - Final geologic unit polygon feature class.  
Contains a "Sph_Area" field containing the area of each 
polygon, as calculated using the spheroid.  Contains a 
"UName" field denoting the unit name.  Contains a "USym" 
field denoting the unit symbol.

Graticule   5 x 5 degree reference graticule as polyline 
feature class.

LinearFeatures - Final structural and morphologic polyline 
feature class.  Contains a "TYPE" field denoting the type 
of linear feature.

LocationFeatures - Final locational feature point feature 
class.  Contains a "TYPE" field denoting the type of 
locational feature.

MapBoundary - Quadrangle boundary as polygon feature class.

Nomenclature - Annotation feature class showing the 
location and extent of approved planetary nomenclature for 
features located wholly or partly within the quadrangle 
boundary.

UnitGroups_COMU - Merged unit polygon feature class.  
Contains a "UnitGroup" field denoting the grouping as 
depicted in figures 1A and 1B of the geologic map.

BASE MAP CONTENT

Image mosaics of Magellan radar backscatter served as the 
primary data set used to delineate boundaries of discrete 
geologic units and to characterize their appearance, 
morphology, and distribution.  Basemap was provided by USGS 
Astrogeology Science Center as an 8-bit raster image 
representing radar backscatter in Lambert Conformal Conic 
projection using the Venus 1985 geographic coordinate 
system.  Topographic data, RMS slope, microwave emissivity, 
and corrected reflectivity data provided supplemental 
information in the identification and description of 
geologic units and features.  These data are available for 
download at: 

     http://www.mapaplanet.org/

DIGITAL DATABASE AND METADATA PACKAGE 
(SIMI3158_database.zip)

The geologic map files, basemap, and supportive files are 
included in the database package, as described below:

File               Description
-----------------------------------------------------------

00_V6_README.txt              This readme file.

SIM3158_metadata.txt          Text-format FGDC-style 
                              metadata for the database 
                              package

SIM3158_metadata.xml          XML-format FGDC-style 
                              metadata for the database 
                              package

SIM3158_MetisMons_5M.mxd      ArcGIS project for the 
                              database package


"Metis_working" directory
--------------------------------------------

MetisMons.gdb                 ArcGIS geodatabase containing 
                              all digital geologic map 
                              information

GeoContacts.lyr               ArcGIS layer file containing 
                              contact symbol look-up table

GeoUnits.lyr                  ArcGIS layer file containing 
                              unit color look-up table

LinearFeatures.lyr            ArcGIS layer file containing 
                              line feature symbol look-up 
                              table

LocationFeatures.lyr          ArcGIS layer file containing 
                              location feature symbol look-
                              up table


"MetisMons_Lambert" directory
--------------------------------------------

"BaseMap" subdirectory
--------------------------------------------

V6_mosaic.tif                 Uncompressed TIFF-format 
                              Magellan radar mosaic

V6_mosaic.tfw                 World file that locates 
                              Magellan radar mosaic

"GriddedData" subdirectory
--------------------------------------------

gedr_emis_l1.tif              Uncompressed TIFF-format 
                              emissivity data

gedr_emis_l1.tfw              World file that locates 
                              emissivity data

gedr_refl_l1.tif              Uncompressed TIFF-format 
                              reflectivity data

gedr_refl_l1.tfw              World file that locates 
                              reflectivity data

gedr_rmsslp_l1.tif            Uncompressed TIFF-format RMS 
                              slope data

gedr_rmsslp_l1.tfw            World file that locates RMS 
                              slope data

gtdr_elev_l1.tif              Uncompressed TIFF-format 
                              elevation data

gtdr_elev_l1.tfw              World file that locates 
                              elevation data


"NoData_mask" subdirectory
--------------------------------------------

V6_mask.tif                   Uncompressed TIFF-format NO 
                              DATA mask

V6_mask.tfw                   World file that locates the 
                              NO DATA mask


Users of the database package may wish to download the 
technical and/or nontechnical pamphlet 
(http://pubs.usgs.gov/sim/3158/) for the contained 
Description of Map Units.

The material described above is available on the World Wide 
Web at http://pubs.usgs.gov/sim/3158/.

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, Redlands, 
California.

OBTAINING HARD-COPY OF SIM-3158

USGS Information Services
Box 25286
Federal Center
Denver, CO  80225-0046

1-888-ASK-USGS (1-888-275-8747)
Email: infoservices@usgs.gov
World Wide Web- http://www.usgs.gov/pubprob

For additional information, please contact:
Astrogeology Science Center
U.S. Geological Survey
2255 N. Gemini Drive
Flagstaff, AZ  86001
http://astrogeology.usgs.gov