Identification_Information: Citation: Citation_Information: Originator: Schaefer, J.R. Publication_Date: 2005 Title: 30-meter shaded relief image of Okmok Volcano, Umnak Island, Alaska Geospatial_Data_Presentation_Form: georeferenced TIFF Series_Information: Series_Name: Raw Data File Issue_Identification: RDF 2005-1 Publication_Information: Publication_Place: Fairbanks, Alaska, United States Publisher: Alaska Division of Geological & Geophysical Surveys Online_Linkage: http://dx.doi.org/10.14509/7041 Description: Abstract: This 30-meter, horizontal, cell-size, shaded relief, georeferenced TIFF image of Okmok Volcano, Umnak Island, Alaska, was created by combining digital elevation model (DEM) data provided by NASA's shuttle radar topography mission (SRTM) and the aircraft-mounted synthetic aperture radar (AirSAR) mission. Purpose: This georeferenced TIFF was created to be used as a base layer for other geographic information system (GIS) projects that display geographic or geologic data pertaining to Okmok Volcano and eastern Umnak Island. This shaded relief image displays topographic features for all of Okmok Volcano, and a small area to the east, across Umnak pass, on Unalaska Island. Supplemental_Information: The DGGS metadata standard extends the FGDC standard to include elements that are required to facilitate our internal data management. These elements, referred to as "layers," group and describe files that have intrinsic logical or topological relationships and correspond to subdirectories within the data distribution package. The metadata layer provides an FGDC metadata file and may include other documentation files. Attribute information for each data layer is described in this metadata file under the "Entity_and_Attribute_Information" section. Data layer contents: >shaded-relief-image: A georeferenced TIFF image of Okmok Volcano, Umnak Island, Alaska Time_Period_of_Content: Time_Period_Information: Multiple_Dates/Times: Single_Date/Time: Calendar_Date: 2003 Single_Date/Time: Calendar_Date: 2004 Currentness_Reference: ground condition Status: Progress: complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -169.046430 East_Bounding_Coordinate: -166.904289 North_Bounding_Coordinate: 54.050037 South_Bounding_Coordinate: 52.949343 Keywords: Theme: Theme_Keyword_Thesaurus: ISO 19115 Topic Category Theme_Keyword: geoscientificInformation Theme: Theme_Keyword_Thesaurus: Alaska Division of Geological & Geophysical Surveys Theme_Keyword: Aleutian Arc Theme_Keyword: Geomorphology Theme_Keyword: Hillshade Image Theme_Keyword: Shaded Relief Theme_Keyword: Volcanoes Place: Place_Keyword_Thesaurus: Alaska Division of Geological & Geophysical Surveys Place_Keyword: Fox Islands Place_Keyword: Okmok Place_Keyword: Okmok Volcano Place_Keyword: Umnak Island Access_Constraints: This report, map, and/or dataset is 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. The 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. The State of Alaska makes no express or implied warranties (including warranties for merchantability and fitness) with respect to the character, functions, or capabilities of the electronic data 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 or any failure thereof or otherwise. In no event will the State of Alaska's liability to the Requestor or anyone else exceed the fee paid for the electronic service or product. Point_of_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: Alaska Division of Geological & Geophysical Surveys Contact_Position: GIS Manager 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_Electronic_Mail_Address: dggsgis@alaska.gov Hours_of_Service: 8 am to 4:30 pm, Monday through Friday, except State holidays Data_Set_Credit: Shuttle Radar Topography Mission (SRTM) DEM data is available for download courtesy of NASA. AirSAR data was provided by NASA JPL via Rick Guritz at the Alaska SAR Facility (ASF) Cross_Reference: 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 Series_Information: Series_Name: Report of Investigation Issue_Identification: RI 2004-3 Publication_Information: Publication_Place: Fairbanks, Alaska, United States Publisher: Alaska Division of Geological & Geophysical Surveys Other_Citation_Details: 32 p., 1 sheet, scale 1:150,000 Online_Linkage: http://dx.doi.org/10.14509/7042 Cross_Reference: Citation_Information: Originator: Schaefer, J.R. Publication_Date: 2005 Title: 30-meter shaded relief image of Okmok Volcano, Umnak Island, Alaska Series_Information: Series_Name: Raw Data File Issue_Identification: RDF 2005-1 Publication_Information: Publication_Place: Fairbanks, Alaska, United States Publisher: Alaska Division of Geological & Geophysical Surveys Online_Linkage: http://dx.doi.org/10.14509/7041 Cross_Reference: Citation_Information: Originator: Schaefer, J.R. Originator: Larsen, J.F. Originator: Unema, J.A. Publication_Date: 2012 Title: Digital elevation model (DEM) and shaded relief image of Okmok Caldera, 2010 Series_Information: Series_Name: Raw Data File Issue_Identification: RDF 2011-6 Publication_Information: Publication_Place: Fairbanks, Alaska, United States Publisher: Alaska Division of Geological & Geophysical Surveys Online_Linkage: http://dx.doi.org/10.14509/23223 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, air-photos, and IKONOS. Completeness_Report: This shaded relief image displays topographic features for all of Okmok Volcano, and 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 accuracey 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 dataset. 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 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 Type_of_Source_Media: on-line Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 2003 Source_Currentness_Reference: ground condition Source_Citation_Abbreviation: NASA SRTM DEM, 2003 Source_Contribution: Convert SRTM DEM files to ArcGRID format 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 Type_of_Source_Media: CD Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 2001 Source_Currentness_Reference: ground condition Source_Citation_Abbreviation: AirSAR DEM, 2001 Source_Contribution: Convert AirSAR DEM files to ArcGRID format Process_Step: Process_Description: Convert SRTM DEM files to ArcGRID format - Two SRTM DEM datasets were downloaded in May 2003 from USGS online repository. The SRTM DEM datasets were converted to ArcGRID format and merged. The merged grid was reprojected to from GCS WGS84 to Universal Transverse Mercator, Zone 2, choosing a cell size of 30 meters. Source_Used_Citation_Abbreviation: NASA SRTM DEM, 2003 Process_Date: 2004 Process_Step: Process_Description: Convert AirSAR DEM files to ArcGRID format - AirSAR DEM data (GeoTIFF format) were provided to DGGS from the Alaska SAR Facility (ASF) in September 2001. The AirSAR DEM GeoTIFF was converted to ArcGRID format. To determine horizontal accuracy, a 10m contour map of the AirSAR DEM ArcGRID was created. The contour lines were overlayed onto IKONOS imagery (see Horizontal_Positional_Accuracy_Report). Based on results discussed in Horizontal_Positional_Accuracy_Report, horizontal correction was applied to the AirSAR DEM ArcGRID file. Source_Used_Citation_Abbreviation: AirSAR DEM, 2001 Process_Date: 2004 Process_Step: Process_Description: Create georeferenced shaded relief TIFF - The horizontally corrected AirSAR DEM ArcGRID file was merged with the SRTM DEM ArcGRID file by replacing all SRTM DEM values less than zero with the AirSAR DEM value. ArcMap 8.2 3D-Analyst extension was used to create a hillshade image GRID with 2x vertical exaggeration. The resulting grid was converted to a georefenced TIFF by adding corner control points (RMS error = 0) and rectifying the image using bilinear interpretation. Process_Date: 2004 Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: raster 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: 0.999600 Longitude_of_Central_Meridian: -171 Latitude_of_Projection_Origin: 0 False_Easting: 500000.000000 False_Northing: 0 Planar_Coordinate_Information: Planar_Coordinate_Encoding_Method: row and column Coordinate_Representation: Abscissa_Resolution: 30.003283 Ordinate_Resolution: 30.003283 Planar_Distance_Units: meters Planar_Coordinate_Layer_Name: shaded-relief-image Geodetic_Model: Horizontal_Datum_Name: World Geodetic System of 1984 Ellipsoid_Name: WGS 84 Semi-major_Axis: 6378137 Denominator_of_Flattening_Ratio: 298.257223563 Entity_and_Attribute_Information: Detailed_Description: Entity_Type: Entity_Type_Label: rdf2005-1-shaded-relief-image Entity_Type_Definition: A georeferenced TIFF image of Okmok Volcano, Umnak Island, Alaska Entity_Type_Definition_Source: Alaska Division of Geological & Geophysical Surveys Entity_Attribute_Layer_Name: shaded-relief-image Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: Alaska Division of Geological & Geophysical Surveys 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_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 website (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: RDF 2005-1 Distribution_Liability: The State of Alaska makes no expressed or implied warranties (including warranties for merchantability and fitness) with respect to the character, functions, or capabilities of the electronic data 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 or any failure thereof or otherwise. In no event will the State of Alaska's liability to the Requestor or anyone else exceed the fee paid for the electronic service or product. Standard_Order_Process: Non-digital_Form: DGGS publications are available as free online downloads or you may purchase paper hard-copies or digital files on CD/DVD or other digital storage media by mail, phone, fax, or email from the DGGS Fairbanks office. 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. Turnaround time is 1-2 weeks unless special arrangements are made and an express fee is paid. Shipping charge will be the actual cost of postage and will be added to the total amount due. Contact us for the exact shipping amount. Fees: Contact DGGS for current pricing Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: GeoTIFF Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: http://dx.doi.org/10.14509/7041 Fees: Free download Metadata_Reference_Information: Metadata_Date: 20140718 Metadata_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: Alaska Division of Geological & Geophysical Surveys Contact_Position: Metadata Manager 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 Metadata_Standard_Name: FGDC Content Standard for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998 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 Alaska Department of Natural Resources or Division of Geological & Geophysical Surveys. Metadata_Extensions: Online_Linkage: http://www.dggs.alaska.gov/metadata/dggs.ext Profile_Name: dggs metadata extensions