Identification_Information: Citation: Citation_Information: Originator: Overbeck, J.R. Originator: Hendricks, M.D. Originator: Kinsman, N.E.M. Publication_Date: 2016 Title: Photogrammetric digital surface models and orthoimagery for 26 coastal communities of western Alaska Geospatial_Data_Presentation_Form: report and digital data Series_Information: Series_Name: Raw Data File Issue_Identification: RDF 2016-1 Publication_Information: Publication_Place: Fairbanks, Alaska, United States Publisher: Alaska Division of Geological & Geophysical Surveys Other_Citation_Details: 3 p. Online_Linkage: http://dx.doi.org/10.14509/29548 Description: Abstract: The State of Alaska Division of Geological & Geophysical Surveys acquired photogrammetric digital surface models (DSMs) and co-registered orthorectified aerial images (orthoimages) for the west coast of Alaska in support of coastal vulnerability mapping efforts. This report is a summary of the data collected over 26 developed areas along approximately 3,500 km of coastline in the Bering Sea, Norton Sound, and Yukon-Kuskokwim Delta regions (fig. 1). Aerial photographs were collected between July 31 and September 6, 2015, and processed using Structure from- Motion (SfM) photogrammetry techniques. Ground control points (GCPs) and checkpoints were collected in support of these data products during a Global Navigation Satellite System (GNSS) survey conducted between August 15 and September 14, 2015. For the purposes of open access to elevation and orthoimagery datasets in coastal regions of Alaska, this collection is being released as a Raw Data File with an open end-user license. The data available for each of the 26 communities consist of the following: (1) Orthoimage raster, (2) Digital Surface Model (DSM) raster, (3) Hillshade raster produced from DSM, and (4) an Orthoimage Hillshade combination raster. Purpose: The State of Alaska Division of Geological & Geophysical Surveys acquired photogrammetric digital surface models (DSMs) and co-registered orthorectified aerial images (orthoimages) for the west coast of Alaska in support of coastal vulnerability mapping efforts. For the purposes of open access to elevation and orthoimagery datasets in coastal regions of Alaska, this collection is being released as a Raw Data File with an open end-user license. Supplemental_Information: >orthoimagery: Orthoimages contain 3-band, 8-bit, unsigned raster data (red/green/blue; the No Data value is set to 0. The file employs Lempel-Ziv-Welch (LZW) compression. Light exposures in the orthoimages are a result of daily weather conditions, which ranged from low cloud cover, rain, and full sun; >digital surface model: The single-band, 32-bit float DSMs represent surface elevations of buildings, vegetation, and uncovered ground surfaces. The No Data value is set to -32767. The file employs LZW compression; >DSM hillshade: The single-band, 8-bit, unsigned integer rasters represent hillshading of the DSM. The No Data value is set to 255. The file employs LZW compression and has the same spatial resolution as the DSM. The hillshade was produced using Blue Marble Geographic's Global Mapper GIS application; >orthoimagery hillshade combination raster: The orthoimagery hillshade combination rasters contain 3-band, 8-bit, unsigned raster data and represents a hillshade-tinted orthoimage. The No Data value is set to 0. The file employs LZW compression. The file was produced with ESRI's ArcGIS using Raster Function templates. This file has the same spatial resolution as its originating DSM; >community data extent polygon file: One polygon shapefile is available that shows the data extent and data attributes for all 26 communities; Note: this file is provided in NAD 1983, UTM Zone 3 coordinates. Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 2015 Currentness_Reference: ground condition Status: Progress: complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -168.133607 East_Bounding_Coordinate: -160.423319 North_Bounding_Coordinate: 65.676650 South_Bounding_Coordinate: 59.803846 Keywords: Theme: Theme_Keyword_Thesaurus: ISO 19115 Topic Category Theme_Keyword: geoscientificInformation Theme: Theme_Keyword_Thesaurus: Alaska Division of Geological & Geophysical Surveys Theme_Keyword: Coastal Theme_Keyword: Coastal and River Theme_Keyword: Engineering Theme_Keyword: Engineering Geology Theme_Keyword: Environmental Theme_Keyword: Geologic Hazards Theme_Keyword: Geology Theme_Keyword: Geomorphology Theme_Keyword: Hillshade Image Theme_Keyword: Methods Theme_Keyword: Orthoimagery Theme_Keyword: Raster Image Place: Place_Keyword_Thesaurus: Alaska Division of Geological & Geophysical Surveys Place_Keyword: Alakanuk Place_Keyword: Alaska, State of Place_Keyword: Brevig Mission Place_Keyword: Chefornak Place_Keyword: Chevak Place_Keyword: Elim Place_Keyword: Emmonak Place_Keyword: Golovin Place_Keyword: Hooper Bay Place_Keyword: Kipnuk Place_Keyword: Kongiganak Place_Keyword: Kotlik Place_Keyword: Koyuk Place_Keyword: Kwigillingok Place_Keyword: Newtok Place_Keyword: Nightmute Place_Keyword: Nome Place_Keyword: Nunam Iqua Place_Keyword: Saint Michael Place_Keyword: Scammon Bay Place_Keyword: Shaktoolik Place_Keyword: Stebbins Place_Keyword: Teller Place_Keyword: Toksook Bay Place_Keyword: Tununak Place_Keyword: Unalakleet Place_Keyword: Wales 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 Rd 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: This publication is funded with qualified outer continental shelf oil and gas revenues by the Coastal Impact Assistance Program, U.S. Fish and Wildlife Service, U.S. Department of the Interior. The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the opinions or policies of the U.S. Government. Mention of trade names or commercial products does not constitute their endorsement by the U.S. Government. Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: Community-specific data quality and reference information can be found in table 1 of the accompanying report. Known anomalies within the data exist on the DSMs over water bodies; these anomalies have not been edited in this data release. Because waves in the nearshore marine or lacustrine environment move at a higher speed than photo-collection, the SfM processing technique for producing DSMs defines those points irregularly (for an example, see fig. 2 of the accompanying report). Logical_Consistency_Report: not applicable Completeness_Report: This data release is complete. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: The aerial survey was planned so flight lines and photograph frequency provided 60 percent side lap and 80 percent end lap photo coverage, with flying heights between 800 and 2,700 ft (244-823 m) resulting in 10-20 cm ground sample distance (GSD; see table 1 of the accompanying report) of the aerial photos. Vertical_Positional_Accuracy: Vertical_Positional_Accuracy_Report: The vertical accuracies of the DSMs were evaluated by comparing both the GCP elevations and checkpoint elevations with the DSM elevations separately for each non-contiguous community (with the exception of Stebbins/Saint Michael, the data are not contiguous between communities). We reduced the residual difference between GCPs and DSM pixels to zero mean using a vertical shift (see table 1). The remaining residuals were used to determine the Root Mean Square Error (RMSE) at each community, then combined to determine RMSE for the dataset as a whole. The final DSMs had a mean vertical residual of 6.2 cm with +/- one standard deviation of 5.2 cm, with 95 percent of all GCP and checkpoint residuals within 16.7 cm. The RMSE of all GCPs and checkpoints was 8.1 cm, but varied by location (see table 1). Lineage: Process_Step: Process_Description: Data processing - Aerial survey GNSS data were processed using Waypoint's Grafnav commercial GNSS software using GPS constellation. Each project was processed using either post-processing kinematic (PPK) or precise point positioning (PPP) methods, depending on the quality of the solution, which was primarily dependent on the distance from Continually Operating Reference Stations (CORS), such that all flights resulted in data with better than 10 cm separation in forward and reverse trajectory solutions. GPS data were processed to the North American Datum 1983 (NAD83; 2011) European Petroleum Survey Group Well Known Identification Number (EPSG) 6318, and the North American Vertical Datum of 1988 (NAVD88; Geoid12A; EPOCH 2010.00). Photos were individually processed for optimum contrast and exposure using Adobe Camera Raw. To accommodate the large data acquisition volumes, most photos were shot and processed to JPEG format. Aerial survey GPS data (event marker coordinates) were manually correlated to image filenames using the image timestamp to create a camera external orientation file for import into Agisoft Photoscan Professional (Photoscan) software. The external orientation file provides the X, Y, Z position of the camera for each photograph taken during the survey. Aerial stereophotographs were imported into the photogrammetric software, which uses an SfM algorithm to create a three-dimensional terrain model from the stereo-imagery. The terrain model was then used to orthometrically correct the photos and produce the final orthoimage mosaic in Photoscan. Within the Photoscan software application, standard workflow steps were followed: photo-alignment, alignment optimization, dense point cloud building, mesh creation, DSM and orthoimage creation, and exporting the results. Process_Date: 2015 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: 3 Transverse_Mercator: Scale_Factor_at_Central_Meridian: 0.999600 Longitude_of_Central_Meridian: -165 Latitude_of_Projection_Origin: 0 False_Easting: 500000.000000 False_Northing: 0 Planar_Coordinate_Information: Planar_Coordinate_Encoding_Method: coordinate pair Coordinate_Representation: Abscissa_Resolution: .00000001 Ordinate_Resolution: .00000001 Planar_Distance_Units: Meters Geodetic_Model: Horizontal_Datum_Name: North American Datum of 1983 Ellipsoid_Name: GRS 80 Semi-major_Axis: 6378137 Denominator_of_Flattening_Ratio: 298.257222101 Vertical_Coordinate_System_Definition: Altitude_System_Definition: Altitude_Datum_Name: NAVD88; Geoid12A; EPOCH 2010.00 Altitude_Resolution: 6.2 Altitude_Distance_Units: centimeters Altitude_Encoding_Method: Implicit coordinate Entity_and_Attribute_Information: Detailed_Description: Entity_Type: Entity_Attribute_Layer_Name: orthoimagery Entity_Type_Label: orthoimagery Entity_Type_Definition: Orthoimages contain 3-band, 8-bit, unsigned raster data (red/green/blue; the No Data value is set to 0. The file employs Lempel-Ziv-Welch (LZW) compression. Light exposures in the orthoimages are a result of daily weather conditions, which ranged from low cloud cover, rain, and full sun; File format: GeoTIFF. Entity_Type_Definition_Source: Fairbanks Fodar Detailed_Description: Entity_Type: Entity_Attribute_Layer_Name: digital surface model Entity_Type_Label: digital surface model Entity_Type_Definition: The single-band, 32-bit float DSMs represent surface elevations of buildings, vegetation, and uncovered ground surfaces. The No Data value is set to -32767. The file employs LZW compression; File format: GeoTIFF. Entity_Type_Definition_Source: Fairbanks Fodar Detailed_Description: Entity_Type: Entity_Attribute_Layer_Name: DSM hillshade Entity_Type_Label: DSM hillshade Entity_Type_Definition: The single-band, 8-bit, unsigned integer rasters represent hillshading of the DSM. The No Data value is set to 255. The file employs LZW compression and has the same spatial resolution as the DSM. The hillshade was produced using Blue Marble Geographic's Global Mapper GIS application; File format: GeoTIFF. Entity_Type_Definition_Source: Alaska Division of Geological & Geophysical Surveys (DGGS) Detailed_Description: Entity_Type: Entity_Attribute_Layer_Name: orthoimagery hillshade combination raster Entity_Type_Label: orthoimagery hillshade combination raster Entity_Type_Definition: The orthoimagery hillshade combination rasters contain 3-band, 8-bit, unsigned raster data and represents a hillshade-tinted orthoimage. The No Data value is set to 0. The file employs LZW compression. The file was produced with ESRI's ArcGIS using Raster Function templates. This file has the same spatial resolution as its originating DSM; File format: GeoTIFF. Entity_Type_Definition_Source: Alaska Division of Geological & Geophysical Surveys (DGGS) Detailed_Description: Entity_Type: Entity_Attribute_Layer_Name: community data extent polygon file Entity_Type_Label: community data extent polygon file Entity_Type_Definition: One polygon shapefile is available that shows the data extent and data attributes for all 26 communities; Note: this file is provided in NAD 1983, UTM Zone 3 coordinates. File format: shapefile. Entity_Type_Definition_Source: Alaska Division of Geological & Geophysical Surveys (DGGS) Overview_Description: Entity_and_Attribute_Overview: Shapefile attribute descriptions for the community data extent polygon file are: >Field: Description >community: Community name >code: 3 digit airport code for community >ortho_gsd: Orthoimage ground sample distance (gsd), that is, raster cell size, in meters >dsm_gsd: DSM ground sample distance (gsd), that is, raster cell size, in meters >vert_shift: Vertical shift, in meters >Rmse: Root mean square error (RMSE) in meters >Num_pts: Number of points used to calculate RMSE >Utm_zone: UTM zone of the delivered data >ortho_gb: Size, in gigabytes, of orthoimage raster file >dsm_gb: Size, in gigabytes, of DSM raster file >dsm_hs_gb: Size, in gigabytes, of DSM hillshade raster file >tint_gb: Size, in gigabytes, of orthoimage hillshade tint raster file Entity_and_Attribute_Detail_Citation: this publication, accompanying report 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 2016-1 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: Shapefiles, Raster data Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: http://dx.doi.org/10.14509/29548 Fees: Free download Metadata_Reference_Information: Metadata_Date: 20160429 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