================================================== Readme file for the Shenandoah Study Area Project ================================================== CD DIRECTORY LAYOUT: |--README.TXT (This file) | | |--Contains Arc/Info coverages for the geologic themes |--DATA---------|--Contains Hillshade Raster in GRID format | | | |--METADATA-----|--Contains metadata of GIS layers used in this study. ================================================== SUMMARY: Map themes for this project were created using various methods. The majority of geologic themes were originally drafted on georeferenced Mylar sheets. These sheets were subsequently scanned and saved as TIF images, vectorized and saved as DXF files, and finally converted to Arc/INFO coverages. Other geologic themes were derived from tabular data. The majority of base map themes were produced from scanned mylars of USGS 1:100,000 topoquads. Following is a list of map themes used in this report categorized by their origin: 1) Created from scanned Mylar: BEDROCK SURFICIAL 2) Produced from DLG's of 1:24,000 USGS Topoquads: County and city Boundaries Place names Hydrography The following is projection information used with all GIS data layers Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Planar: Grid_Coordinate_System: Grid_Coordinate_System_Name: Universal Transverse Mercator Universal_Transverse_Mercator: UTM_Zone_Number: 17 Transverse_Mercator: Scale_Factor_at_Central_Meridian: 0.999600 Longitude_of_Central_Meridian: -81.000000 Latitude_of_Projection_Origin: 0.000000 False_Easting: 500000.000000 False_Northing: 0.000000 Planar_Coordinate_Information: Planar_Coordinate_Encoding_Method: coordinate pair Coordinate_Representation: Abscissa_Resolution: 0.000061 Ordinate_Resolution: 0.000061 Planar_Distance_Units: meters Geodetic_Model: Horizontal_Datum_Name: North American Datum of 1927 Ellipsoid_Name: Clarke 1866 Semi-major_Axis: 6378206.400000 Denominator_of_Flattening_Ratio: 294.978698 ================================================== Please feel free to contact me with any questions. Boris J. Barrios E-mail: bbarrios@usgs.gov