DESCRIPTION OF THE DIGITAL DATABASE FOR Geologic Map of the Vashon 7.5' Quadrangle and Selected Areas, King County, Washington By Derek B. Booth, Kathy Goetz Troost, and Rowland W. Tabor USGS SCIENTIFIC INVESTIGATIONS MAP 3328 2015 INTRODUCTION This digital database for the Geologic Map of the Vashon 7.5' Quadrangle and Selected Areas, King County, Washington (USGS SIM 3328) includes several ArcInfo coverages (individual vector datasets) along with supporting files and metadata. The coverages have been converted to ArcInfo export files. Relative to coverages, ArcInfo export files are easier to transport from one ArcInfo installation to another and are usable by some other Geographic Information Systems. All GIS data are in STATEPLANE projection, zone 5601, units FEET, SPHEROID, GRS1980 horizontal datum NAD83 (Lambert Conformal Conic, but see metadata for covers for details). Together with the geologic pamphlet, the database provides georeferenced information on the geologic structure and stratigraphy of the area covered. The database delineates map units that are identified by general age and lithology following the stratigraphic nomenclature of the U.S. Geological Survey. The spatial resolution (scale) of the database is 1:24,000 or less. The content and character of the database, as well as how to obtain the database, are described below. This database contains five ArcInfo coverages with geologic content and two with basemap content: GEOLOGIC CONTENT VASHGEOL Network coverage with arcs, polygons, and polygon label points. VASHSTRUCT Point coverage of bedding plane strikes and dips with orientation data VASHDBSTAT Point cover of field stations; shown as Field exposure on geologic map VASHLINES Arc coverage with location of till beds too thin to show at map scale and cross-section lines VASHEXPT Arc coverage of locations of geotechnical exploration sites BASE MAP CONTENT VASHDRAIN Arc coverage showing digitized streams and rivers VASHRDS Arc coverage of roads DIGITAL DATABASE AND METADATA PACKAGE (sim3328_database.zip) The ARC export files and associated ArcInfo coverages, as well as the additional digital material included in the database package, are described below: File Description ------------------------------------------------------------- sim3328readme.txt This readme file vashcrelief.tif Uncompressed TIFF-format georeferenced shaded relief image with geologic map unit colors vashrelief.tfw World file that locates vashrelief.tif in Stateplane projection, units feet, datum NAD83 vashgeol-genmd.txt Text-format FGDC-style metadata for the database package as a whole Each coverage within the Geology and Base subdirectories contains detailed hml-format FGDC-style metadata specific to the coverage. This metadata is stored as file metadata.hml within the coverage directory, and is read with a web browsers (e.g., Firefox, Safari, Internet Explorer) Geology subdirectory -------------------- vashgeol.e00 ArcInfo export file of geologic contacts, faults, and generalized map units vashstruct.e00 ArcInfo export file of bedding strike and dip vashlines.e00 Arcinfo export file of till beds and cross-section lines vashdbstat.e00 Arc info export file of station map vashexpt.e00 Arc info export file of geotechnical exploration sites Base subdirectory ----------------- vashrds.e00 ArcInfo export file of roads vashdrain.e00 ArcInfo export file of Drainage network Users of the database package may wish to download the pamphlet (sim3328_pamphlet.pdf for the contained Description of Map Units or the pdf of the geologic map. The material described above is available on the World-Wide Web at http://pubs.usgs.gov/sim/3328/ or http://dx.doi.org/10.3133/sim3328. ZIP FILES The files described above are packaged within a ZIP file (GIS.zip). Utilities to uncompress ZIP files are available for most all operating systems and may be found readily with a simple web search. DIGITAL DATABASE FORMAT The databases in this report were compiled in ArcInfo, a commercial Geographic Information System (Environmental Systems Research Institute, Redlands, California. ArcInfo coverages were converted to uncompressed ARC export files (.e00 extention, ArcInfo version 9.3 for Windows XP). These export files can be converted into back into coverages in ArcInfo with the IMPORT command, e.g., Arc: import cover xxx.e00 xxx where xxx is the coverage name. The files can also be read by some other Geographic Information Systems. While specifications for the .e00 format has not been published by Environmental Systems Research Institute, the files are plain ASCII, the structure is relatively easy to decode and 3rd-party descriptions are available via Web search for ".e00 format". OBTAINING THE DIGITAL DATABASE Go to http://pubs.usgs.gov/sim/3328/ or http://dx.doi.org/10.3133/sim3328 to access the database package and the remainder of this publication. ACKNOWLEDGMENTS We thank Karen Wheeler for review of this readme, the database package, and associated metadata.