Identification_Information: Citation: Citation_Information: Originator: Buzard, R.M. Originator: Christian, J.E. Originator: Overbeck, J.R. Publication_Date: 2021 Title: Photogrammetry-derived orthoimagery and elevation for Alakanuk, Alaska, collected July 11, 2021 Geospatial_Data_Presentation_Form: GeoTIFF Series_Information: Series_Name: Raw Data File Issue_Identification: RDF 2021-17 Publication_Information: Publication_Place: Fairbanks, Alaska, United States Publisher: Alaska Division of Geological & Geophysical Surveys Other_Citation_Details: 4 p. Online_Linkage: https://doi.org/10.14509/30790 Description: Abstract: The State of Alaska Division of Geological & Geophysical Surveys (DGGS) collected low-altitude aerial images from an unmanned aerial vehicle (UAV) on July 11, 2021 and used Structure-from-Motion (SfM) photogrammetry to produce a digital surface model (DSM) and orthoimage of Alakanuk. The orthoimage and elevation data are for assessing coastal hazards and changes. We used Trimble Business Center to process the Global Navigation Satellite System (GNSS) data used for positional control. We used Agisoft Metashape to process the photogrammetry data. These products are released as a Raw Data File with an open end-user license. All files can be downloaded from the Alaska Division of Geological & Geophysical Surveys website (http://doi.org/10.14509/30790). Purpose: The orthoimage and elevation data are for assessing coastal hazards and changes near Alakanuk. Supplemental_Information: >digital surface model: The DSM represents surface elevations such as the height of vegetation and buildings. Water bodies can introduce noise. We manually delineated the river boundaries to restrict the DSM to the land. The DSM is a single-band, 32-bit floating point GeoTIFF file with a GSD of 0.068 m, the "No Data" value is set to -3.4028231 x 10^38. >orthoimagery: The orthoimage is a three-band (red, green, blue) 8-bit unsigned GeoTIFF file with a GSD of 0.034 m per pixel, the "No Data" value is set to 0. Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 20210711 Currentness_Reference: ground condition Status: Progress: complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -164.687390 East_Bounding_Coordinate: -164.617980 North_Bounding_Coordinate: 62.699571 South_Bounding_Coordinate: 62.674027 Keywords: Theme: Theme_Keyword_Thesaurus: ISO 19115 Topic Category Theme_Keyword: geoscientificInformation Theme: Theme_Keyword_Thesaurus: Alaska Division of Geological & Geophysical Surveys Theme_Keyword: Aerial Theme_Keyword: Aerial Geology Theme_Keyword: Aerial Photography Theme_Keyword: Coastal Theme_Keyword: Coastal Erosion Theme_Keyword: Coastal Plain Theme_Keyword: Coastal and River Theme_Keyword: DGGS Theme_Keyword: Digital Surface Model (DSM) Theme_Keyword: Elevation Theme_Keyword: Emergency Preparedness Theme_Keyword: Engineering Theme_Keyword: Engineering Geology Theme_Keyword: Environmental Theme_Keyword: Erosion Theme_Keyword: Flood Theme_Keyword: Floodplain Theme_Keyword: Fluvial Theme_Keyword: Geologic Theme_Keyword: Geologic Hazards Theme_Keyword: Geological Process Theme_Keyword: Geology Theme_Keyword: Geomorphology Theme_Keyword: Geotechnical Theme_Keyword: Hazards Theme_Keyword: Orthoimagery Theme_Keyword: Photogrammetry Theme_Keyword: Raster Image Theme_Keyword: Remote Sensing Theme_Keyword: River Erosion Theme_Keyword: Structure From Motion Theme_Keyword: Surface Theme_Keyword: Surficial Theme_Keyword: Surficial Geology Theme_Keyword: Topography Theme_Keyword: Unconsolidated Deposits Theme_Keyword: Water Theme_Keyword: Web Service Place: Place_Keyword_Thesaurus: Alaska Division of Geological & Geophysical Surveys Place_Keyword: Alakanuk Place_Keyword: Southwest Alaska Place_Keyword: Yukon Delta Place_Keyword: Yukon River 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: 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 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 (https://www.dggs.alaska.gov) for the latest information on available data. Please contact us using the e-mail address provided above when possible. Data_Set_Credit: We thank the Alakanuk Village for funding and supporting the creation of these data products. Cross_Reference: Citation_Information: Originator: Buzard, R.M. Originator: Overbeck, J.R. Originator: Maio, C.V. Publication_Date: 2019 Title: Community-based methods for monitoring coastal erosion Series_Information: Series_Name: Information Circular Issue_Identification: IC 84 Publication_Information: Publication_Place: Fairbanks, Alaska, United States Publisher: Alaska Division of Geological & Geophysical Surveys Other_Citation_Details: 35 p Online_Linkage: https://doi.org/10.14509/30182 Cross_Reference: Citation_Information: Originator: Buzard, R.M. Originator: Turner, M.M. Originator: Miller, K.Y. Originator: Antrobus, D.C. Originator: Overbeck, J.R. Publication_Date: 2021 Title: Erosion exposure assessment of infrastructure in Alaska coastal communities Series_Information: Series_Name: Report of Investigation Issue_Identification: RI 2021-3 Publication_Information: Publication_Place: Fairbanks, Alaska, United States Publisher: Alaska Division of Geological & Geophysical Surveys Other_Citation_Details: 29 p Online_Linkage: https://doi.org/10.14509/30672 Cross_Reference: Citation_Information: Originator: Overbeck, J.R. Publication_Date: 2018 Title: Coastal flooding & erosion in Alaska Series_Information: Series_Name: Information Circular Issue_Identification: IC 68 Publication_Information: Publication_Place: Fairbanks, Alaska, United States Publisher: Alaska Division of Geological & Geophysical Surveys Other_Citation_Details: 2 p Online_Linkage: https://doi.org/10.14509/30057 Cross_Reference: Citation_Information: Originator: Overbeck, J.R. Originator: Buzard, R.M. Originator: Turner, M.M. Originator: Miller, K.Y. Originator: Glenn, R.J. Publication_Date: 2020 Title: Shoreline change at Alaska coastal communities Series_Information: Series_Name: Report of Investigation Issue_Identification: RI 2020-10 Publication_Information: Publication_Place: Fairbanks, Alaska, United States Publisher: Alaska Division of Geological & Geophysical Surveys Other_Citation_Details: 29 p., 47 sheets Online_Linkage: https://doi.org/10.14509/30552 Cross_Reference: 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 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: https://doi.org/10.14509/29548 Cross_Reference: Citation_Information: Originator: Overbeck, J.R. Originator: Hendricks, M.D. Originator: Kinsman, N.E.M. Publication_Date: 2017 Title: Photogrammetric digital surface models and orthoimagery for the continuous coastline, Wales to Platinum, Alaska Series_Information: Series_Name: Raw Data File Issue_Identification: RDF 2017-8 Publication_Information: Publication_Place: Fairbanks, Alaska, United States Publisher: Alaska Division of Geological & Geophysical Surveys Other_Citation_Details: 21 p Online_Linkage: https://doi.org/10.14509/29744 Cross_Reference: Citation_Information: Originator: Overbeck, J.R. Publication_Date: 2018 Title: Alaska coastal mapping gaps & priorities Series_Information: Series_Name: Information Circular Issue_Identification: IC 72 Publication_Information: Publication_Place: Fairbanks, Alaska, United States Publisher: Alaska Division of Geological & Geophysical Surveys Other_Citation_Details: 34 p Online_Linkage: https://doi.org/10.14509/30096 Cross_Reference: Citation_Information: Originator: Wolken, G.J. Originator: Hendricks, K.A. Originator: Daanen, R.P. Originator: Overbeck, J.R. Originator: Stevens, D.S.P. Originator: Masterman, S.S. Publication_Date: 2017 Title: Alaska & climate change Series_Information: Series_Name: Information Circular Issue_Identification: IC 64 Publication_Information: Publication_Place: Fairbanks, Alaska, United States Publisher: Alaska Division of Geological & Geophysical Surveys Other_Citation_Details: 2 p Online_Linkage: https://doi.org/10.14509/29781 Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: Not applicable Logical_Consistency_Report: DGGS visually inspected the orthoimage for data errors such as shifts, seamline mismatches, and water noise overlapping land. There were no significantly erroneous areas that required repair. Visual errors common to these SfM photogrammetry products include discontinuous powerlines, blurriness near high-angle features like buildings, and distortion at water boundaries. Bright objects like metal roofs and white paint can cause overexposure, leading to spurious elevation points. Completeness_Report: This data release is complete. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: We quantify the horizontal accuracy of the DSM and orthoimage by comparing the known locations of 16 photo-identifiable check points measured with GNSS against their modeled locations in the photogrammetric products. X and Y errors are calculated as the root-mean-square (RMS) error of offsets. The total horizontal error is the root-sum-square error of X and Y RMS errors, 0.048 m. See accompanying report for a table of check point coordinates and offsets from orthoimage and DSM. Vertical_Positional_Accuracy: Vertical_Positional_Accuracy_Report: We assess the vertical accuracy of the DSM using the same check points. The RMS error of Z offsets is 0.041 m. The total error of the DSM (X, Y, and Z) is 0.063 m. Lineage: Process_Step: Process_Description: Airborne survey - DGGS used a DJI Phantom 4 RTK UAV with a FC6310R camera model (8.8 mm lens) to collect 20-megapixel JPEG photographs (5472 x 3648 pixels per image). We flew the aerial survey with 70 percent sidelap and 80 percent frontlap, 120 m above the ground at 7.9 m/s, with nadir camera orientation stabilized by a 3-axis gimbal. The resulting images cover 2.42 km2 with ground sampling distance (GSD) of approximately 0.03 m. DGGS conducted flights on July 11, 2021, from 5:30 to 8:45 PM AKDT. The operator returned the UAV eight times to change batteries. The weather was favorable with overcast clouds, no rain, and light wind. No abnormalities were observed during the flights. Process_Date: 20210711 Process_Step: Process_Description: Ground survey - DGGS set up a GNSS base station using a Trimble R10 receiver sampling at 5 Hz. The base was installed over a temporary benchmark of unknown position. This provided real-time kinematic (RTK) corrections to the UAV and Trimble R8s GNSS receiver. DGGS measured 21 photo-identifiable points with the R8s. We derived the corrected base position using the Online Positioning User Service (found at www.ngs.noaa.gov/OPUS/) and post-processed the R8s positions in Trimble Business Center. Process_Date: 20210711 Process_Step: Process_Description: Photogrammetric dataset processing - The UAV maintained RTK connection throughout the survey. The RTK system automatically applies the lever arm correction when writing camera GNSS coordinates (WGS84 ellipsoid) to the image metadata. Yaw, pitch, and roll information were not written to the image metadata. We update UAV positions using a X, Y, and Z shift from the initial to the corrected base position. DGGS processed images in Agisoft Metashape Professional software (Version 1.6.3 build 10732). We masked image corners where shadows and image warping were disruptive. Processing steps included aligning images, identifying ground control points (GCPs), manually cleaning the sparse point cloud, optimizing the bundle block adjustment (refining camera positions and lens distortion parameters), constructing the dense point cloud, building the DSM, and creating the orthomosaic image. We used five GCPs to create the model, leaving sixteen survey check points. Process_Date: 2021 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: NAD83 (2011) Ellipsoid_Name: GRS 80 Semi-major_Axis: 6378137 Denominator_of_Flattening_Ratio: 298.257222101000025 Vertical_Coordinate_System_Definition: Altitude_System_Definition: Altitude_Datum_Name: NAVD88, GEOID12B Altitude_Resolution: 0.001 Altitude_Distance_Units: meters Altitude_Encoding_Method: Explicit elevation coordinate included with horizontal coordinates Entity_and_Attribute_Information: Detailed_Description: Entity_Type: Entity_Type_Label: digital surface model Entity_Type_Definition: The DSM represents surface elevations such as the height of vegetation and buildings. Water bodies can introduce noise. We manually delineated the river boundaries to restrict the DSM to the land. The DSM is a single-band, 32-bit floating point GeoTIFF file with a GSD of 0.068 m, the "No Data" value is set to -3.4028231 x 10^38. Entity_Type_Definition_Source: DGGS Entity_Attribute_Layer_Name: digital surface model Detailed_Description: Entity_Type: Entity_Type_Label: orthoimagery Entity_Type_Definition: The orthoimage is a three-band (red, green, blue) 8-bit unsigned GeoTIFF file with a GSD of 0.034 m per pixel, the "No Data" value is set to 0. Entity_Type_Definition_Source: DGGS Entity_Attribute_Layer_Name: orthoimagery Distribution_Information: Distributor: 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 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 (https://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 2021-17 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 Format_Version_Date: 20211209 Format_Information_Content: digital surface model and orthoimagery Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: https://doi.org/10.14509/30790 Fees: Free download Metadata_Reference_Information: Metadata_Date: 20211210 Metadata_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: Alaska Division of Geological & Geophysical Surveys Contact_Person: Simone Montayne 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 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 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: https://dggs.alaska.gov/metadata/dggs.ext Profile_Name: dggs metadata extensions