{"action":"create","ckan_id":null,"date_created":"Wed, 11 Mar 2026 06:10:11 GMT","date_finished":null,"harvest_job_id":"6b9e775f-8424-4547-8b0a-acba57df116a","harvest_source_id":"f4c7bbab-c7ef-4277-a7d3-c25b78854814","id":"ac7240d2-7e0b-4e32-8159-b46bdd11e286","identifier":"https://dggs.alaska.gov/webpubs/metadata/RI2004-3_basemap.xml","parent_identifier":null,"source_hash":"d9cf86193a608041b5c9813cfa9e8ebd8198d8ad843190ff36d57554b5cca42a","source_raw":"\r\n\r\n\r\n\r\n\r\nBeget, J.E.\r\nLarsen, J.F.\r\nNeal, C.A.\r\nNye, C.J.\r\nSchaefer, J.R.\r\n2005\r\nPreliminary volcano-hazard assessment for Okmok Volcano, Umnak Island, Alaska\r\nraster digital data\r\n\r\nReport of Investigation\r\nRI 2004-3\r\n\r\n\r\nFairbanks, AK\r\nState of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys\r\n\r\n1 sheet, scale 1:150,000\r\nhttp://dx.doi.org/10.14509/7042\r\n\r\n\r\n\r\nThis shaded relief image of Okmok Volcano serves as the basemap for sheet 1 of the "Preliminary volcano-hazard assessment for Okmok Volcano, Umnak Island, Alaska" (DGGS RI 2004-3). The map area is centered around Okmok Volcano, on eastern Umnak Island. SRTM and AirSAR DEM datasets were combined in ArcGIS to produce a georeferenced shaded relief TIFF image of Okmok Volcano.\r\nThis shaded relief image was created to illustrate, at a scale of 1:150,000, the approximate location of volcanic hazard zones around Okmok Volcano.\r\n\r\nThis basemap is a modified version of Schaefer, Janet R., 2005, 30-meter shaded relief image of Okmok Volcano, Umnak Island, Alaska: Alaska Division of Geological & Geophysical Surveys Raw Data File RDF 2005-1, 1 CD. The bulk of the image is based on the SRTM data, but many data holes or shadows in the original SRTM data have been filled in with the AirSAR data to create a better display. Missing data appear as black pixels, especially in steep terrain. The SRTM data was collected during an 11-day mission in February 2000, and the AirSAR data was collected on October 17, 2000. Attribute information for the following layers (entities) is included in this metadata file under the "Entity_and_Attribute_Information" section. Each layer is listed and described in detail under its own heading starting "Entity_Type_Label." Layers include:\r\n>OKhazbase basemap, modified from Schaefer, 2005, 30-meter shaded relief image of Okmok Volcano, Umnak Island, Alaska\r\n\r\n\r\n\r\n\r\n\r\n20000212\r\n\r\n\r\nground condition\r\n\r\n\r\nComplete\r\nnone planned\r\n\r\n\r\n\r\n-168.7576\r\n-167.5153\r\n53.7312\r\n53.1099\r\n\r\n\r\n\r\n-168.7262 53.7312, -167.5153 53.7020, -167.5634 53.1099, -168.7576 53.1384\r\n\r\n\r\n\r\n\r\n\r\nISO 19115 Topic Category\r\ngeoscientificInformation\r\n\r\n\r\nnone\r\nAleutian Arc\r\nVolcanoes\r\n\r\n\r\nnone\r\nAleutian Islands\r\nFort Glenn\r\nFox Islands\r\nOkmok, Mount\r\nOkmok Caldera\r\nUmnak Island\r\n\r\n\r\nThis report, map, and/or dataset are available directly from the State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys (see contact information below).\r\nAny hard copies or published datasets utilizing these datasets shall clearly indicate their source. If the user has modified the data in any way, the user is obligated to describe the types of modifications the user has made. User specifically agrees not to misrepresent these datasets, nor to imply that changes made by the user were approved by the State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys.\r\n\r\n\r\n\r\nState of Alaska, Division of Geological & Geophysical Surveys\r\n\r\nAlaska Volcano Observatory Geologist III\r\n\r\nmailing and physical address\r\n
3354 College Road
\r\nFairbanks\r\nAK\r\n99709-3707\r\nUSA\r\n\r\n(907) 451-5010\r\nNot Available\r\n(907) 451-5050\r\ndggspubs@alaska.gov\r\n8 am to 4:30 pm Monday through Friday, except State holidays\r\nPlease address all comments or questions to the e-mail address above whenever possible.\r\n\r\n\r\nThis dataset was compiled by the authors with funds from the Alaska Volcano Observatory, a joint program of the U.S. Geological Survey, the University of Alaska Fairbanks-Geophysical Institute, and the Alaska Division of Geological & Geophysical Surveys.\r\nMicrosoft Windows XP SP1, ArcGIS 8.2, MapInfo, and any text editor. This georeferenced TIFF comes with both an ESRI world file (.tfw) and a MapInfo tab (.tab) file and can be used in any GIS software that reads a tif/tfw or tif/tab pair.\r\n\r\n\r\nSchaefer, Janet R.\r\n2005\r\n30-meter shaded relief image of Okmok Volcano, Umnak Island, Alaska\r\nraster digital data\r\n\r\nRaw Data File\r\nRDF 2005-1\r\n\r\n\r\nFairbanks, AK\r\nState of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys\r\n\r\n1 CD\r\nhttp://dx.doi.org/10.14509/7041\r\n\r\n\r\n\r\n\r\n\r\nRGB values of the hillshade were computed from the DEM data using ESRI software Arc 8.2 3-D analyst extension.\r\n\r\nShaded relief image was checked for accurate display of topographic features with on-the-ground inspection (geologic fieldwork), helicopter overflights, and imagery sets such as Landsat7, airphotos, and IKONOS.\r\nThis shaded relief image displays topographic features for all of Okmok Volcano, and only a very small area to the east, across Umnak pass, on Unalaska Island. It was originally intended as a base layer for the display of geographic, geologic, and volcano-hazard features of Okmok Volcano, at a scale of 1:150,000.\r\n\r\n\r\nSub-meter horizontal/vertical accuracy GPS points that were acquired during the summer field season 2000 and 2001 were used to assess the geospatial accuracy of IKONOS remotely sensed imagery. The GPS data collection points were chosen so that they would be visible and distinguishable on the imagery. In a GIS, the GPS points were overlain on the georeferenced IKONOS imagery. The horizontal geospatial accuracy of the remotely sensed imagery was determined to be less than 15 meters. This imagery was then used as the geospatially accurate reference to determine the precision of the DEM data. A 10-meter contour map was made of each DEM dataset. The contour map based on the SRTM DEM data was overlain on the sub-15-meter accurate IKONOS imagery. Visual inspections at a zoom scale of 1:3,000 determined that the horizontal accuracy was correct and no adjustments were made to the SRTM DEM data. The contour map based on the AirSAR DEM data, however, appeared to be inaccurate (creeks did not line up with V-contours, high points did not line up with high-point closed contours, etc.). At a zoom scale of 1:3,000, ten visually distinguishable points were chosen to determine an X-shift and Y-shift needed to align the AirSAR DEM-derived contour data to the imagery. Results (average and standard deviation reported): X = 41 +/- 9 meters, Y = 198 +/- 19 meters. A shift of X = -41 and Y = 198 was applied to the AirSAR DEM data set.\r\n\r\n60\r\n60 meters corresponds to 2 raster cells. An accuracy of less than 60 meters, or 2 cell sizes, is observed for all visually recognizable data points that can be used to compare the IKONOS imagery to the DEM-derived contour data.\r\n\r\n\r\n\r\nAlthough the vertical data cannot be directly derived from this TIFF data, this vertical positional accuracy report was written to qualify the resulting shade effect that has been derived from a conversion between vertical value and RGB hillshade value. After an assessment of the horizontal accuracy was complete, it was then possible to assess the vertical accuracy (see Horizontal_Positional_Accuracy_Report). Thirty-five sub-meter horizontal/vertical accuracy GPS points that were acquired during the summer field season 2000 and 2001 were used to assess the vertical accuracy. A calculation of the known GPS vertical value minus the SRTM DEM vertical value for the same horizontal position showed that the SRTM vertical data was under-estimating the elevation by 19.3 +/- 4.3 meters (mean and standard deviation of the 35 points reported). Twenty-nine GPS points were used in the same way to assess the vertical accuracy of the AirSAR DEM data. The results of the GPS minus AirSAR vertical values for the same horizontal point (after the X-Y shift was applied) are -0.3 +/- 5.44 (mean and standard deviation reported for 29 points). In conclusion, the vertical values for the SRTM DEM dataset overestimate the true vertical value by about 19 meters, and the AirSAR DEM data vertical values are accurate to about 5 meters. Prior to creating the shaded relief image, these two datasets were combined by filling in any holes of the SRTM data with the AirSAR data. The bulk of the data used to derive the shaded relief image came from the SRTM data, and therefore the vertical accuracy for the values used to create the shaded relief image are taken to be about 19 meters. This agrees well with the NASA reported error for the dataset, which is 20 meters.\r\n\r\n\r\n\r\n\r\n\r\n\r\nNASA Jet Propulsion Laboratory (JPL) and the National Geospatial-Intelligence Agency\r\n2003\r\nShuttle Radar Topography Mission (SRTM) DEM data, files N53W168.hdr and N53W169.hdr\r\nftp edition\r\nraster digital data\r\n\r\nInitial release\r\n2003\r\n\r\n\r\nunknown\r\nU.S. Geological Survey\r\n\r\n2 digital files\r\nftp://edcsgs9.cr.usgs.gov/pub/data/srtm/United_States_1arcsec/1arcsec/\r\n\r\n\r\non-line\r\n\r\n\r\n\r\n20000212\r\n\r\n\r\nground condition\r\n\r\nNASA SRTM DEM, 2003\r\n1-arc second DEM data\r\n\r\n\r\n\r\n\r\nNASA Jet Propulsion Laboratory (JPL) and the Alaska SAR Facility (ASF)\r\n2001\r\nAirSAR DEM data for Okmok Volcano\r\nSeptember 2001\r\nraster digital data\r\n\r\nInitial release\r\nSeptember 2001\r\n\r\n\r\nFairbanks, AK\r\nAlaska SAR Facility\r\n\r\n1 CD\r\nNONE\r\n\r\n\r\nCD\r\n\r\n\r\n\r\n200009\r\n\r\n\r\nground condition\r\n\r\nAirSAR DEM, 2001\r\n5-meter DEM data\r\n\r\n\r\n\r\nProcess Step 1 - Convert SRTM DEM data to ArcGRID\r\nTwo SRTM DEM data sets were downloaded in May 2003 from the ftp site\r\nftp://edcsgs9.cr.usgs.gov/pub/data/srtm/United_States_1arcsec/1arcsec/\r\nFiles N53W168.hdr.zip and N53W169.hdr.zip\r\n\r\n1. Unzip SRTM DEM data file\r\nunzip FILENAME.hgt.zip\r\n\r\n2. Rename using lower case letters\r\nmv FILENAME.hgt filename.bil\r\n\r\n3. Make a hdr text file with the same name as the filename.bil, but call it filename.hdr\r\nfor example, below is a header file called n53w167.hdr\r\n\r\nBYTEORDER M\r\nLAYOUT BIL\r\nNROWS 3601\r\nNCOLS 3601\r\nNBANDS 1\r\nNBITS 16\r\nBANDROWBYTES 7202\r\nTOTALROWBYTES 7202\r\nBANDGAPBYTES 0\r\nNODATA -32768\r\nULXMAP -167.0\r\nULYMAP 54.0\r\nXDIM 0.000277777777777\r\nYDIM 0.000277777777777\r\n\r\nNote that the SRTM naming convention specifies the lower left corner coordinates, while the hdr file needs the upper left coordinates (ULXMAP, ULYMAP). The variables ULXMAP and ULYMAP are the only two variables that will change with each new hdr file.\r\n\r\n4. Create a grid using the arc command imagegrid\r\nArc - imagegrid filename.bil filename\r\n\r\nIMAGEGRID does not support conversion of signed image data, therefore the\r\nnegative 16-bit DEM values will not be interpreted correctly. After running\r\nIMAGEGRID, an easy fix can be accomplished using the following formula in Grid:\r\n\r\nout_grid = con(in_grid >= 32768, in_grid - 65536, in_grid)\r\n\r\nThe converted grid will then have the negative values properly represented,\r\nand the statistics of the grid should match those listed in the .ANN file.\r\n\r\n5. Repeat steps 1 through 4 for both SRTM DEM data files.\r\n\r\n6. Merge the two data files in Arc Grid\r\nGrid - out_grid = merge(grid1, grid2)\r\n\r\n7. Using Project wizard in ArcToolbox, reproject the merged grid from GCS WGS84 to Transverse Mercator, Zone 2, choosing a cell size of 30 meters.\r\n\r\nNASA SRTM DEM, 2003\r\n2004\r\n\r\n\r\n\r\nJanet R. Schaefer\r\nState of Alaska, Division of Geological & Geophysical Surveys\r\n\r\nAlaska Volcano Observatory Geologist III\r\n\r\nmailing and physical address\r\n
3354 College Road
\r\nFairbanks\r\nAK\r\n99709-3707\r\nUSA\r\n\r\n(907) 451-5010\r\nNot Available\r\n(907) 451-5050\r\ndggspubs@alaska.gov\r\n8 am to 4:30 pm, Monday through Friday, except State holidays\r\nPlease address all comments or questions to the e-mail address above whenever possible.\r\n\r\n\r\n\r\n\r\nProcess Step 2 - Convert AirSAR DEM to Arc Grid. (1) AirSAR data were delivered to DGGS from the Alaska SAR Facility (ASF) in September 2001 in a geoTIFF format. (2) GeoTIFF was converted to an Arc grid using IMAGEGRID function in Arc. (3) Created a 10m contour map of the Arc grid and overlayed contour lines onto IKONOS imagery to determine horizontal accuracy (see Horizontal_Positional_Accuracy_Report). (4) Determined new values for xmin and ymin based on results discussed in Horizontal_Positional_Accuracy_Report. Applied shift to AirSAR DEM Arc Grid using the following command in Arc Grid newgrid = shift(oldgrid, newxmin, newymin).\r\nAirSAR DEM, 2001\r\n2004\r\n\r\n\r\n\r\nJanet R. Schaefer\r\nState of Alaska, Division of Geological & Geophysical Surveys\r\n\r\nAlaska Volcano Observatory Geologist III\r\n\r\nmailing and physical address\r\n
3354 College Road
\r\nFairbanks\r\nAK\r\n99709-3707\r\nUSA\r\n\r\n(907) 451-5010\r\nNot Available\r\n(907) 451-5050\r\ndggspubs@alaska.gov\r\n8 am to 4:30 pm, Monday through Friday, except State holidays\r\nPlease address all comments or questions to the e-mail address above whenever possible.\r\n\r\n\r\n\r\n\r\nProcess Step 3 - Merge the AirSAR and SRTM DEMs and create a georeferenced shaded relief TIFF. (1) Merge the horizontally corrected AirSAR Arc grid with the SRTM DEM Arc Grid in Arc Grid by replacing all SRTM DEM values less than zero with the AirSAR DEM value. Grid: newgrid = con(srtmdemgrid < 0, airsardem, srtmdemgrid). (2)In ArcMap 8.2, create a hillshade with 2x vertical exaggeration using 3D-Analyst extension. (3) Clip the grid using GRIDCLIP command to encompass an area suitable for displaying hazard zones around Okmok Volcano (see bounding coordinate information). (4)Convert the resulting hillshaded grid into a TIFF using the Arc command GRIDIMAGE. Grid: GRIDIMAGE in_grid NONE out_image TIFF. (5)In ArcMap 8.2, georeference the image to UTM Zone 2, WGS 84, by adding corner control points. RMS error = 0. Update georeferencing, then rectify using bilinear interpretation. (5) Modify the tiff in Corel Photopaint to a 24-bit RGB image and change the color of the ocean (outer black pixels) to blue.\r\n2004\r\n\r\n\r\n\r\nJanet R. Schaefer\r\nState of Alaska, Division of Geological & Geophysical Surveys\r\n\r\nAlaska Volcano Observatory Geologist III\r\n\r\nmailing and physical address\r\n
3354 College Road
\r\nFairbanks\r\nAK\r\n99709-3707\r\nUSA\r\n\r\n(907) 451-5010\r\nNot Available\r\n(907) 451-5050\r\ndggspubs@alaska.gov\r\n8 am to 4:30 pm, Monday through Friday, except State holidays\r\nPlease address all comments or questions to the e-mail address above whenever possible.\r\n\r\n\r\n\r\n\r\n\r\n\r\nRaster\r\n\r\nPixel\r\n2200\r\n2667\r\n1\r\n\r\n\r\n\r\n\r\n\r\n\r\nUniversal Transverse Mercator\r\n\r\n2\r\n\r\n0.9996\r\n-171.0000\r\n0.0000\r\n500000.0000\r\n0.0000\r\n\r\n\r\n\r\n\r\nrow and column\r\n\r\n30.003283\r\n30.003283\r\n\r\nmeters\r\n\r\n\r\n\r\nWGS 1984\r\nWGS 1984\r\n6378137.0000\r\n298.257224\r\n\r\n\r\n\r\n\r\n\r\n\r\nOKhazbase.tif\r\nObject type is raster, describing a basemap, modified from Schaefer, 2005, 30-meter shaded relief image of Okmok Volcano, Umnak Island, Alaska\r\nAlaska Division of Geological & Geophysical Surveys\r\nOKhazbase\r\n\r\n\r\nFile Type\r\nThe file format of the image\r\nAlaska Division of Geological & Geophysical Surveys\r\n\r\nTIFF, 24-bit RGB color mode\r\n\r\n\r\n\r\nFile Size\r\nThe file size of the video\r\nAlaska Division of Geological & Geophysical Surveys\r\n\r\n16.7 Mb\r\n\r\n\r\n\r\nLine (row)\r\nThe number of lines or rows in the image\r\nAlaska Division of Geological & Geophysical Surveys\r\n\r\n\r\n1\r\n2200\r\npixels\r\n\r\n\r\n\r\n\r\nSample (column)\r\nThe number of samples or columns in the image\r\nAlaska Division of Geological & Geophysical Surveys\r\n\r\n\r\n1\r\n2667\r\npixels\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\nState of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys\r\n\r\nNatural Resource Technician\r\n\r\nmailing and physical\r\n
3354 College Road
\r\nFairbanks\r\nAK\r\n99709-3707\r\nUSA\r\n\r\n907-451-5020\r\nNone available.\r\n907-451-5050\r\ndggspubs@alaska.gov\r\n8 am to 4:30 pm, Monday through Friday, except State holidays\r\nPlease view our web site (http://www.dggs.alaska.gov) for the latest information on available data. Please contact us using the e-mail address provided above when possible.\r\n\r\n\r\nReport of Investigation 2004-3\r\nThe State of Alaska makes no express or implied warranties (including warranties of merchantability and fitness) with respect to the character, function, or capabilities of the electronic services or products or their appropriateness for any user's purposes. In no event will the State of Alaska be liable for any incidental, indirect, special, consequential, or other damages suffered by the user or any other person or entity whether from the use of the electronic services or products, any failure thereof, or otherwise, and in no event will the State of Alaska's liability to the requester or anyone else exceed the fee paid for the electronic service or product.\r\n\r\nCurrent publication is available on paper. To purchase this or other printed reports and maps, contact DGGS by phone (907-451-5020), e-mail (dggspubs@alaska.gov), or fax (907-451-5050). Payment accepted: Cash, check, money order, VISA, or MasterCard.\r\nPrinted publication can be purchased for $17.00 (contact information below) plus shipping if mailed.\r\n\r\n\r\n\r\n\r\nTIFF\r\n2005\r\nNo compression applied\r\n\r\n\r\n\r\n\r\n\r\nhttp://dx.doi.org/10.14509/7042\r\n\r\n\r\n\r\n\r\nCD-ROM\r\nJoliet\r\n\r\n\r\n\r\nDigital files on CD-ROM are available for $10.00 (contact information below). No fees charged for downloaded files.\r\nOrder by phone (907-451-5020), e-mail (dggspubs@alaska.gov), or fax (907-451-5050). The DGGS web site (http://www.dggs.alaska.gov/) has a list of electronic data available and an order form that can be printed. Payment accepted: Cash, check, money order, VISA, or MasterCard.\r\nDigital downloads: less than 30 minutes for most files. Offline CD/DVD-ROMs: 1-2 weeks unless special arrangements are made and an express fee is paid.\r\n\r\nGeospatial software is required to view and manipulate this shaded relief image, such as ENVI <http://www.ittvis.com/envi/>, ER Mapper <http://www.ermapper.com/> or ESRI ArcGIS <http://www.esri.com/software/arcgis/index.html>. Free versions of the software listed may be available to simply view the data.\r\n\r\n\r\n20080506\r\n20080506\r\n20091003\r\n\r\n\r\n\r\nState of Alaska, Division of Geological & Geophysical Surveys\r\nJanet R. Schaefer\r\n\r\nAlaska Volcano Observatory Geologist III\r\n\r\nmailing and physical address\r\n
3354 College Road
\r\nFairbanks\r\nAK\r\n99709-3707\r\nUSA\r\n\r\n(907) 451-5010\r\n(907) 451-5050\r\ndggspubs@alaska.gov\r\n8 am to 4:30 pm, Monday through Friday, except State holidays.\r\nPlease contact us through the e-mail address above whenever possible.\r\n\r\n\r\nFGDC Content Standard for Digital Geospatial Metadata\r\nFGDC-STD-001-1998\r\nnone\r\nIf the user has modified the data in any way they are obligated to describe the types of modifications they have performed in the supporting metadata file. User specifically agrees not to imply that changes they made were approved by the State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys.\r\n\r\n\r\n","source_transform":null,"status":"error"}