Identification_Information: Citation: Citation_Information: Originator: Beget, J.E. Originator: Larsen, J.F. Originator: Neal, C.A. Originator: Nye, C.J. Originator: Schaefer, J.R. Publication_Date: 2005 Title: Preliminary volcano-hazard assessment for Okmok Volcano, Umnak Island, Alaska Geospatial_Data_Presentation_Form: raster digital data Series_Information: Series_Name: Report of Investigation Issue_Identification: RI 2004-3 Publication_Information: Publication_Place: Fairbanks, AK Publisher: State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys Other_Citation_Details: 1 sheet, scale 1:150,000 Online_Linkage: http://dx.doi.org/10.14509/7042 Description: Abstract: This 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. Purpose: This shaded relief image was created to illustrate, at a scale of 1:150,000, the approximate location of volcanic hazard zones around Okmok Volcano. Supplemental_Information: This 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: >OKhazbase basemap, modified from Schaefer, 2005, 30-meter shaded relief image of Okmok Volcano, Umnak Island, Alaska Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 20000212 Currentness_Reference: ground condition Status: Progress: Complete Maintenance_and_Update_Frequency: none planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -168.7576 East_Bounding_Coordinate: -167.5153 North_Bounding_Coordinate: 53.7312 South_Bounding_Coordinate: 53.1099 Data_Set_G-Polygon: Data_Set_G-Polygon_Outer_G-Ring: G-Ring: -168.7262 53.7312, -167.5153 53.7020, -167.5634 53.1099, -168.7576 53.1384 Keywords: Theme: Theme_Keyword_Thesaurus: ISO 19115 Topic Category Theme_Keyword: geoscientificInformation Theme: Theme_Keyword_Thesaurus: none Theme_Keyword: Aleutian Arc Theme_Keyword: Volcanoes Place: Place_Keyword_Thesaurus: none Place_Keyword: Aleutian Islands Place_Keyword: Fort Glenn Place_Keyword: Fox Islands Place_Keyword: Okmok, Mount Place_Keyword: Okmok Caldera Place_Keyword: Umnak Island Access_Constraints: This 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). Use_Constraints: Any 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. Point_of_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: State of Alaska, Division of Geological & Geophysical Surveys Contact_Position: Alaska Volcano Observatory Geologist III Contact_Address: Address_Type: mailing and physical address Address: 3354 College Road City: Fairbanks State_or_Province: AK Postal_Code: 99709-3707 Country: USA Contact_Voice_Telephone: (907) 451-5010 Contact_TDD/TTY_Telephone: Not Available Contact_Facsimile_Telephone: (907) 451-5050 Contact_Electronic_Mail_Address: dggspubs@alaska.gov Hours_of_Service: 8 am to 4:30 pm Monday through Friday, except State holidays Contact_Instructions: Please address all comments or questions to the e-mail address above whenever possible. Data_Set_Credit: This 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. Native_Data_Set_Environment: Microsoft 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. Cross_Reference: Citation_Information: Originator: Schaefer, Janet R. Publication_Date: 2005 Title: 30-meter shaded relief image of Okmok Volcano, Umnak Island, Alaska Geospatial_Data_Presentation_Form: raster digital data Series_Information: Series_Name: Raw Data File Issue_Identification: RDF 2005-1 Publication_Information: Publication_Place: Fairbanks, AK Publisher: State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys Other_Citation_Details: 1 CD Online_Linkage: http://dx.doi.org/10.14509/7041 Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: RGB values of the hillshade were computed from the DEM data using ESRI software Arc 8.2 3-D analyst extension. Logical_Consistency_Report: Shaded 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. Completeness_Report: This 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. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: Sub-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. Quantitative_Horizontal_Positional_Accuracy_Assessment: Horizontal_Positional_Accuracy_Value: 60 Horizontal_Positional_Accuracy_Explanation: 60 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. Vertical_Positional_Accuracy: Vertical_Positional_Accuracy_Report: Although 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. Lineage: Source_Information: Source_Citation: Citation_Information: Originator: NASA Jet Propulsion Laboratory (JPL) and the National Geospatial-Intelligence Agency Publication_Date: 2003 Title: Shuttle Radar Topography Mission (SRTM) DEM data, files N53W168.hdr and N53W169.hdr Edition: ftp edition Geospatial_Data_Presentation_Form: raster digital data Series_Information: Series_Name: Initial release Issue_Identification: 2003 Publication_Information: Publication_Place: unknown Publisher: U.S. Geological Survey Other_Citation_Details: 2 digital files Online_Linkage: ftp://edcsgs9.cr.usgs.gov/pub/data/srtm/United_States_1arcsec/1arcsec/ Type_of_Source_Media: on-line Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 20000212 Source_Currentness_Reference: ground condition Source_Citation_Abbreviation: NASA SRTM DEM, 2003 Source_Contribution: 1-arc second DEM data Source_Information: Source_Citation: Citation_Information: Originator: NASA Jet Propulsion Laboratory (JPL) and the Alaska SAR Facility (ASF) Publication_Date: 2001 Title: AirSAR DEM data for Okmok Volcano Edition: September 2001 Geospatial_Data_Presentation_Form: raster digital data Series_Information: Series_Name: Initial release Issue_Identification: September 2001 Publication_Information: Publication_Place: Fairbanks, AK Publisher: Alaska SAR Facility Other_Citation_Details: 1 CD Online_Linkage: NONE Type_of_Source_Media: CD Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 200009 Source_Currentness_Reference: ground condition Source_Citation_Abbreviation: AirSAR DEM, 2001 Source_Contribution: 5-meter DEM data Process_Step: Process_Description: Process Step 1 - Convert SRTM DEM data to ArcGRID Two SRTM DEM data sets were downloaded in May 2003 from the ftp site ftp://edcsgs9.cr.usgs.gov/pub/data/srtm/United_States_1arcsec/1arcsec/ Files N53W168.hdr.zip and N53W169.hdr.zip 1. Unzip SRTM DEM data file unzip FILENAME.hgt.zip 2. Rename using lower case letters mv FILENAME.hgt filename.bil 3. Make a hdr text file with the same name as the filename.bil, but call it filename.hdr for example, below is a header file called n53w167.hdr BYTEORDER M LAYOUT BIL NROWS 3601 NCOLS 3601 NBANDS 1 NBITS 16 BANDROWBYTES 7202 TOTALROWBYTES 7202 BANDGAPBYTES 0 NODATA -32768 ULXMAP -167.0 ULYMAP 54.0 XDIM 0.000277777777777 YDIM 0.000277777777777 Note 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. 4. Create a grid using the arc command imagegrid Arc - imagegrid filename.bil filename IMAGEGRID does not support conversion of signed image data, therefore the negative 16-bit DEM values will not be interpreted correctly. After running IMAGEGRID, an easy fix can be accomplished using the following formula in Grid: out_grid = con(in_grid >= 32768, in_grid - 65536, in_grid) The converted grid will then have the negative values properly represented, and the statistics of the grid should match those listed in the .ANN file. 5. Repeat steps 1 through 4 for both SRTM DEM data files. 6. Merge the two data files in Arc Grid Grid - out_grid = merge(grid1, grid2) 7. Using Project wizard in ArcToolbox, reproject the merged grid from GCS WGS84 to Transverse Mercator, Zone 2, choosing a cell size of 30 meters. Source_Used_Citation_Abbreviation: NASA SRTM DEM, 2003 Process_Date: 2004 Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Janet R. Schaefer Contact_Organization: State of Alaska, Division of Geological & Geophysical Surveys Contact_Position: Alaska Volcano Observatory Geologist III Contact_Address: Address_Type: mailing and physical address Address: 3354 College Road City: Fairbanks State_or_Province: AK Postal_Code: 99709-3707 Country: USA Contact_Voice_Telephone: (907) 451-5010 Contact_TDD/TTY_Telephone: Not Available Contact_Facsimile_Telephone: (907) 451-5050 Contact_Electronic_Mail_Address: dggspubs@alaska.gov Hours_of_Service: 8 am to 4:30 pm, Monday through Friday, except State holidays Contact_Instructions: Please address all comments or questions to the e-mail address above whenever possible. Process_Step: Process_Description: Process 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). Source_Used_Citation_Abbreviation: AirSAR DEM, 2001 Process_Date: 2004 Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Janet R. Schaefer Contact_Organization: State of Alaska, Division of Geological & Geophysical Surveys Contact_Position: Alaska Volcano Observatory Geologist III Contact_Address: Address_Type: mailing and physical address Address: 3354 College Road City: Fairbanks State_or_Province: AK Postal_Code: 99709-3707 Country: USA Contact_Voice_Telephone: (907) 451-5010 Contact_TDD/TTY_Telephone: Not Available Contact_Facsimile_Telephone: (907) 451-5050 Contact_Electronic_Mail_Address: dggspubs@alaska.gov Hours_of_Service: 8 am to 4:30 pm, Monday through Friday, except State holidays Contact_Instructions: Please address all comments or questions to the e-mail address above whenever possible. Process_Step: Process_Description: Process 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. Process_Date: 2004 Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Janet R. Schaefer Contact_Organization: State of Alaska, Division of Geological & Geophysical Surveys Contact_Position: Alaska Volcano Observatory Geologist III Contact_Address: Address_Type: mailing and physical address Address: 3354 College Road City: Fairbanks State_or_Province: AK Postal_Code: 99709-3707 Country: USA Contact_Voice_Telephone: (907) 451-5010 Contact_TDD/TTY_Telephone: Not Available Contact_Facsimile_Telephone: (907) 451-5050 Contact_Electronic_Mail_Address: dggspubs@alaska.gov Hours_of_Service: 8 am to 4:30 pm, Monday through Friday, except State holidays Contact_Instructions: Please address all comments or questions to the e-mail address above whenever possible. Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Raster Raster_Object_Information: Raster_Object_Type: Pixel Row_Count: 2200 Column_Count: 2667 Vertical_Count: 1 Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Planar: Grid_Coordinate_System: Grid_Coordinate_System_Name: Universal Transverse Mercator Universal_Transverse_Mercator: UTM_Zone_Number: 2 Transverse_Mercator: Scale_Factor_at_Central_Meridian: 0.9996 Longitude_of_Central_Meridian: -171.0000 Latitude_of_Projection_Origin: 0.0000 False_Easting: 500000.0000 False_Northing: 0.0000 Planar_Coordinate_Information: Planar_Coordinate_Encoding_Method: row and column Coordinate_Representation: Abscissa_Resolution: 30.003283 Ordinate_Resolution: 30.003283 Planar_Distance_Units: meters Geodetic_Model: Horizontal_Datum_Name: WGS 1984 Ellipsoid_Name: WGS 1984 Semi-major_Axis: 6378137.0000 Denominator_of_Flattening_Ratio: 298.257224 Entity_and_Attribute_Information: Detailed_Description: Entity_Type: Entity_Attribute_Layer_Name: OKhazbase Entity_Type_Label: OKhazbase.tif Entity_Type_Definition: Object type is raster, describing a basemap, modified from Schaefer, 2005, 30-meter shaded relief image of Okmok Volcano, Umnak Island, Alaska Entity_Type_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute: Attribute_Label: File Type Attribute_Definition: The file format of the image Attribute_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute_Domain_Values: Unrepresentable_Domain: TIFF, 24-bit RGB color mode Attribute: Attribute_Label: File Size Attribute_Definition: The file size of the video Attribute_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute_Domain_Values: Unrepresentable_Domain: 16.7 Mb Attribute: Attribute_Label: Line (row) Attribute_Definition: The number of lines or rows in the image Attribute_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 1 Range_Domain_Maximum: 2200 Attribute_Units_of_Measure: pixels Attribute: Attribute_Label: Sample (column) Attribute_Definition: The number of samples or columns in the image Attribute_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 1 Range_Domain_Maximum: 2667 Attribute_Units_of_Measure: pixels Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys Contact_Position: Natural Resource Technician Contact_Address: Address_Type: mailing and physical Address: 3354 College Road City: Fairbanks State_or_Province: AK Postal_Code: 99709-3707 Country: USA Contact_Voice_Telephone: 907-451-5020 Contact_TDD/TTY_Telephone: None available. Contact_Facsimile_Telephone: 907-451-5050 Contact_Electronic_Mail_Address: dggspubs@alaska.gov Hours_of_Service: 8 am to 4:30 pm, Monday through Friday, except State holidays Contact_Instructions: Please 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. Resource_Description: Report of Investigation 2004-3 Distribution_Liability: The 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. Standard_Order_Process: Non-digital_Form: Current 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. Fees: Printed publication can be purchased for $17.00 (contact information below) plus shipping if mailed. Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: TIFF Format_Version_Date: 2005 File_Decompression_Technique: No compression applied Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: http://dx.doi.org/10.14509/7042 Offline_Option: Offline_Media: CD-ROM Recording_Format: Joliet Fees: Digital files on CD-ROM are available for $10.00 (contact information below). No fees charged for downloaded files. Ordering_Instructions: Order 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. Turnaround: Digital 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. Technical_Prerequisites: Geospatial software is required to view and manipulate this shaded relief image, such as ENVI , ER Mapper or ESRI ArcGIS . Free versions of the software listed may be available to simply view the data. Metadata_Reference_Information: Metadata_Date: 20080506 Metadata_Review_Date: 20080506 Metadata_Future_Review_Date: 20091003 Metadata_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: State of Alaska, Division of Geological & Geophysical Surveys Contact_Person: Janet R. Schaefer Contact_Position: Alaska Volcano Observatory Geologist III Contact_Address: Address_Type: mailing and physical address Address: 3354 College Road City: Fairbanks State_or_Province: AK Postal_Code: 99709-3707 Country: USA Contact_Voice_Telephone: (907) 451-5010 Contact_Facsimile_Telephone: (907) 451-5050 Contact_Electronic_Mail_Address: dggspubs@alaska.gov Hours_of_Service: 8 am to 4:30 pm, Monday through Friday, except State holidays. Contact_Instructions: Please contact us through the e-mail address above whenever possible. Metadata_Standard_Name: FGDC Content Standard for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998 Metadata_Access_Constraints: none Metadata_Use_Constraints: If 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.