DESCRIPTION OF THE DIGITAL DATABASE FOR GEOLOGIC MAP OF THE NORTH CASCADE RANGE, WASHINGTON USGS SCIENTIFIC INVESTIGATIONS MAP 2940 INTRODUCTION This digital database for the Geologic Map of the North Cascade Range (USGS SIM-2940) 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 UTM projection, zone 10, units meters, horizontal datum NAD27. 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 1:200,000 or less. The content and character of the database, as well as two methods of obtaining the database, are described below. GEOLOGIC CONTENT This database contains 3 ArcInfo coverages with geologic content: NCGEOLMAP Final compilation coverage. Network coverage with arcs, polygons, and polygon label points. This coverage should be the starting point for follow-on analyses and compilation. NCG Preliminary compilation coverage. Network coverage with arcs, polygons, and polygon label points. NCGROCKSAMP Point coverage with locations, rock units, sample numbers, and (in some cases) brief descriptions of about 2,700 rock samples that are in the custody of North Cascades National Park, Marblemount, Washington The authors compiled geologic-map source databases into a single database using Arc Macro Language (AML) scripts written by R.A. Haugerud. These scripts combined the source databases, correlated and simplified their units, and removed polygons of surficial deposits that are too small to show at 1:200,000 compilation scale. R.W. Tabor and Haugerud further edited this digital compilation, correcting a few minor drafting errors that were present in the source databases, adjusting some mismatches at source-map boundaries, and eliminating some map-unit polygons too small to show at 1:200,000 scale. This simplified 1:200,000 compilation is ArcInfo coverage NCG. For cartographic purposes, the network coverage ncg was used to produce a coverage of map-unit polygons and a fault coverage. K. Nimz made further minor edits to these derivative coverages in the course of producing the published geologic map image. Haugerud recombined the edited derivative coverages and corrected further minor drafting and compilation errors to produce network coverage NCGEOLMAP. Minor shifts of feature coordinates during GIS processing have led to slight differences (mostly less than few meters in ground coordinates) in the coordinates of equivalent features in the published map image and coverages NCG and NCGEOLMAP. These differences are not significant. We recommend that GIS analyses of this map database start with coverage NCGEOLMAP. Coverage NCG is of interest for its documentation of feature sources. The authors used nine 1:100,000 scale geologic map databases as sources for NCG and NCGEOLMAP. Six of these have been published and three are unpublished. These databases are: Tabor, R.W., Waitt, R.B., Frizzell, V.A., Jr., Swanson, D.A., Byerly, G.R., and Bentley, R.D., 1982, Geologic map of the Wenatchee 1:100,000 quadrangle, central Washington: U.S. Geological Survey Miscellaneous Investigations Map I-1311, scale 1:100,000, 26 p. Tabor, R.W., Frizzell, V.A., Jr., Whetten, J.T., Waitt, R.B., Swanson, D.A., Byerly, G.R., Booth, D.B., Hetherington, M.J., and Zartman, R.E., 1987, Geologic map of the Chelan 30-minute by 60-minute quadrangle, Washington: U.S. Geological Survey Miscellaneous Investigations Map I-1661, scale 1:100,000, 29 p. Tabor, R.W., Frizzell, V.A., Jr., Booth, D.B., Waitt, R.B., Whetten, J.T., and Zartman, R.E., 1993, Geologic map of the Skykomish 60-minute by 30-minute quadrangle, Washington: U.S. Geological Survey Geologic Investigations Series I-1963, scale 1:100,000, 42 p. Tabor, R.W., Frizzell, V.A., Jr., Booth, D.B., and Waitt, R.B., 2000, Geologic map of the Snoqualmie Pass 30- x 60-minute quadrangle, Washington: U.S. Geological Survey Geologic Investigations Series Map I-2538, scale 1:100,000, 57 p. Tabor, R.W., Booth, D.B., and Ford, A.B., 2002, Geologic map of the Sauk 30- x 60-minute quadrangle, Washington: U.S. Geological Survey Geologic Investigations Series I-2592, scale 1:100,000, 67 p. Tabor, R.W., Haugerud, R.A., Hildreth, W., and Brown, E.H., 2003, Geologic map of the Mount Baker 30- x 60-minute quadrangle, Washington: U.S. Geological Survey Geologic Investigations Series Map I-2660, scale 1:100,000, 73 p. Haugerud, R.A, and Tabor, R.W., unpublished, Geologic map of the Robinson Mountain 30- x 60 minute quadrangle, Washington, scale 1:100,000. Haugerud, R.A, Mahoney, J.B., and Tabor, R.W., unpublished, Geologic map of the northeast part of the Twisp 30- x 60 minute quadrangle, Washington, scale 1:100,000. Tabor, R.W., compiler, unpublished, Geologic map of the western and southern parts of the Twisp 30- by 60-minute quadrangle and part of the Chelan 30- by 60-minute quadrangle, Washington, with revision of some surficial deposits from aerial photographs, scale 1:100,000. The sources of new data in the Robinson Mountain and Twisp 1:100,000-scale unpublished compilations are described in the technical pamphlet that accompanies this database. Tabor digitized most of the points in NCGROCKSAMP from scale-stable original sample location maps at 1:100,000 scale. He digitized the locations of samples in the Cascade Pass area and in the Glacier Peak 15-minute quadrangle from scale-stable compilations at 1:24,000 and 1:62,500 scale, respectively. BASE MAP CONTENT Tabor and Haugerud compiled the shaded-relief base for this 1:200,000 map from a 20-meter subsample of U.S.G.S 10 meter DEMs. The DEMs, which are a standard USGS product derived from existing 1;24,000-scale topographic maps, are available at http://wagda.lib.washington.edu/data/type/drg/ Drainage and cultural features were extracted from U.S.G.S. 1:100,000-scale digital line graphs, available at: http://edcftp.cr.usgs.gov/pub/data/DLG/100K/ The authors digitized additional trails by inspection of 1:24,000-scale topographic maps and U.S. Forest Service maps. Most geographic and cultural names derive from U.S. Geological Survey databases which may be found at http://geonames.usgs.gov/domestic/download_data.htm K. Nimz assisted with final edits to the base-map data. DIGITAL DATABASE AND METADATA PACKAGE (sim2940_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 ------------------------------------------------------------------------------------ 00README.txt This readme tile ncgrelief.tif Uncompressed TIFF-format shaded relief image with geologic map unit colors ncgrelief.tfw World file that locates ncgrelief.tif in UTM10 projection, units meters, datum NAD27 sim2940_metadata.txt Text-format FGDC-style metadata for the database package as a whole sim2940_metadata.xml XML-format FGDC-style metadata for the database package as a whole Each coverage within the Geology and Base subdirectories contains detailed XML-format FGDC-style metadata specific to the coverage. This metadata is stored as file metadata.xml within the coverage directory, and is easily browsed from within ArcCatalog, or read with a web browsers (e.g., Firefox, Safari, Internet Explorer) Geology subdirectory -------------------- ncg.e00 ArcInfo export file of eight appended 1:100,000-scale geologic quadrangles: contacts, faults, and source-map units. Generalized map units identified ncgeolmap.e00 ArcInfo export file of geologic contacts, faults, and generalized map units as simplified for 1:200,000 scale compilation ncgrocksamp.e00 ArcInfo export file of point locations of about 2700 rock samples archived at North Cascades National Park, Marblemount, WA Base subdirectory ----------------- ncgculines.e00 ArcInfo export file of roads and trails ncgdrain.e00 ArcInfo export file of Drainage network including man-made irrigation works, with river, stream, and glacier names in annotation layer (anno.water) ncgpwbound.e00 ArcInfo export file of boundaries of North Cascade National Park and Wilderness Areas ncgmapbound.e00 ArcInfo export file of the boundaries of 8 30- x 60-minute quadrangles used in compilation ncgcobound.e00 ArcInfo export file of boundaries of Washington counties in the map area ncgpeakpts.e00 ArcInfo export file of summits of mountains named on map ncgculanno.e00 ArcInfo export file of annotation for all cultural features on map. This coverage holds the annotation in several levels: $level 1 = wilderness area and other boundary names $level 2 = Mountains, peaks, ridges, buttes, etc. $level 3 = passes, valleys, mines, ridges, rocks $level 4 = cities and towns $level 5 = county names Drainage annotation is in cover ncgdrain Users of the database package may wish to download the technical and (or) nontechnical pamphlet (sim2940_technical.pdf or sim2940_nontechnical.pdf) for the contained Description of Map Units. The material described above is available on the CD included with the map report and on the World-Wide Web at http://pubs.usgs.gov/sim/2940/. ZIP FILES The files described above are packaged within a ZIP file. 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/2940/ to access the database package and the remainder of this publication. OBTAINING HARD COPY OF SIM-2940 USGS Information Services Box 25286 Denver Federal Center Denver, CO 80225-0046 (303)202-4200 1-888-ASK-USGS FAX: (303)202-4695 e-mail: infoservices@usgs.gov ACKNOWLEDGEMENTS We thank Karen Wheeler for review of this readme, the database package, and associated metadata.