bbefcad3-e402-474a-8c52-aa9b5ad7b061_source eng; USA utf8 dataset Simone Montayne Alaska Division of Geological & Geophysical Surveys Metadata Manager (907)451-5020 (907)451-5050 3354 College Road Fairbanks AK 99709-3707 USA dggspubs@alaska.gov 8 am to 4:30 pm, Monday through Friday, except State holidays pointOfContact 2022-11-14 ISO 19115 Geographic Information - Metadata ISO 19115:2003/Cor.1:2006(E) Photogrammetry-derived orthoimagery and elevation data for Pilot Point, Alaska, collected June 1-3, 2021 2022-01-01 publication Alaska Division of Geological & Geophysical Surveys Fairbanks Alaska, United States publisher Bogardus, R.C. originator Glenn, R.J.T. originator Nessel, O.B. originator Maio, C.V. originator Horen, K.C. originator https://doi.org/10.14509/30905 DATA Raw Data File RDF 2022-13 4 p. Photogrammetry-derived orthoimagery and elevation data for Pilot Point, Alaska, collected June 1-3, 2021, Raw Data File 2022-13, uses low-altitude aerial images, collected from an unmanned aerial vehicle (UAV) on June 1 and June 3, 2021, and Structure-from-Motion (SfM) photogrammetry to produce a digital surface model (DSM) and orthoimagery for the community of Pilot Point, Alaska. 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 and NOAA VDatum to adjust elevation data. We used Agisoft Metashape to process 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/10.14509/30905). The orthoimage and elevation data were collected for assessing coastal hazards and changes. We thank the Native Village of Pilot Point for funding supporting the creation of these data products. These data were produced by the University of Alaska Fairbanks Arctic Coastal Geoscience Lab (UAF-AGCL). The DGGS Coastal Hazards Program and UAF-AGCL work collaboratively to collect baseline data in Alaska communities and to produce raw data file publications for public access and archiving. completed Alaska Division of Geological & Geophysical Surveys Metadata Manager (907)451-5020 (907)451-5050 3354 College Road Fairbanks AK 99709-3707 USA dggspubs@alaska.gov 8 am to 4:30 pm, Monday through Friday, except State holidays 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. pointOfContact notPlanned Aerial Aerial Geology Aerial Photography Coastal Coastal Erosion Coastal Plain Coastal and River Coastal and River Hazards DGGS Digital Surface Model (DSM) Elevation Emergency Preparedness Engineering Environmental Erosion Flood Floodplain Geologic Geologic Hazards Geology Geomorphology Geophysics Geotechnical Hazards Marine Geology Photogrammetry Raster Image Remote Sensing Sea Level Changes Shoreface Surface Surface Water Surficial Surficial Geology Water theme Alaska Division of Geological & Geophysical Surveys Pilot Point place Alaska Division of Geological & Geophysical Surveys 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. otherRestrictions 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. otherRestrictions 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). Community-based methods for monitoring coastal erosion 2019-01-01 publication Alaska Division of Geological & Geophysical Surveys Fairbanks Alaska, United States publisher Buzard, R.M. originator Overbeck, J.R. originator Maio, C.V. originator https://doi.org/10.14509/30182 Information Circular IC 84 35 p crossReference Coastal flooding & erosion in Alaska 2018-01-01 publication Alaska Division of Geological & Geophysical Surveys Fairbanks Alaska, United States publisher Overbeck, J.R. originator https://doi.org/10.14509/30057 Information Circular IC 68 2 p crossReference grid eng; USA geoscientificInformation -157.603124 -157.588624 57.594345 57.615181 2022-06-01 2022-06-03 >digital surface model: The DSM represents surface elevations such as the height of vegetation and buildings. Since water bodies can introduce noise, we selectively removed areas manually where inland water bodies introduced excessive noise. The DSM is a single-band, 32-bit floating point GeoTIFF file with a GSD of 0.13 m; the No Data value is set to -32767. >orthoimagery: The orthoimage is a three-band (red, green, blue), 16-bit unsigned GeoTIFF file with a GSD of 0.065 m per pixel; the No Data value is set to 0. true data unknown Alaska Division of Geological & Geophysical Surveys Metadata Manager (907)451-5020 (907)451-5050 3354 College Road Fairbanks AK 99709-3707 USA dggspubs@alaska.gov 8 am to 4:30 pm, Monday through Friday, except State holidays 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. distributor Contact DGGS for current pricing Free download https://doi.org/10.14509/30905 data digital surface model and orthoimagery information dataset Horizontal Positional Accuracy Report We quantify the horizontal accuracy of the DSM and orthoimage by comparing the known locations of 19 photo-identifiable check points measured with GNSS against their modeled locations in the photogrammetric products. These are independent checkpoints not used in processing. 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, 0.073 m See accompanying report for a table of checkpoints and further discussion of factors impacting the certainty of data locations. Vertical Positional Accuracy Report We assess the vertical accuracy of the DSM using the same check points. The RMS error of Z offsets is 0.083 m. The total error of the DSM (X, Y, and Z) is 0.111 m. See the accompanying report for check points and additional detail. This data relaease is complete. This data relaease is complete. ACGL 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 such as buildings, and distortion at water boundaries. Bright objects, such as metal roofs and white paint, can cause overexposure and lead to spurious elevation points. This lineage was generated by the FGDC CSDGM to 19139 transformation Aerial photogrammetric survey - ACGL used a DJI Phantom 3 Advanced UAV with an FC300S camera model (3.61 mm lens) to collect 12-megapixel JPEG photographs (4000 x 3000 pixels per image). We flew the aerial survey with 80 percent sidelap and 80 percent frontlap, 120 m above the ground at between 7.5 m/s, with nadir orientation stabilized using a 3-axis gimbal. This resulted in 788 images covering 0.6 km2 with ground sampling distance (GSD) of 0.07 m. ACGL conducted flights between June 1 and June 3, 2021, from 10:00 AM to 4:00 PM AKDT. The operator returned the UAV four times to change batteries. The weather throughout the survey was favorable with little to no clouds, no rain, and no wind. No abnormalities were observed during the flights. 2022-06-03T00:00:00 Ground survey - ACGL set up a GNSS base station using the Trimble R8 receiver sampling at 1 Hz. The base was installed over a temporary benchmark of unknown position. This provided real-time kinematic (RTK) corrections to the UAV and Trimble R2 GNSS receiver (ground rover). The corrected base position was derived using the Online Positioning User Service, found at http://www.ngs.noaa.gov/OPUS/. The R2s' positions were updated using post-processing kinematic (PPK) corrections in Trimble Business Center. ACGL measured 117 photo-identifiable ground control points (GCPs) with the ground rover, 98 of which were utilized for georeferencing during processing. The remaining 19 were reserved for quality control checks. 2022-01-01T00:00:00 Photogrammetric dataset processing - During the survey, the UAV maintained RTK connection. Within the UAV GNSS receiver settings, the lever arm correction is automatically applied and camera GNSS coordinates are written to the image metadata in WGS84 ellipsoid. Yaw, pitch, and roll information are not written to the image metadata. During processing we update UAV positions using an X, Y, and Z shift from the initial to corrected base position. ACGL processed the data in Agisoft Metashape Professional software (Version 1.5.5 build 7618). Processing steps included aligning images, identifying GCPs, manually cleaning the sparse point cloud, optimizing the bundle block adjustment (refining camera position and lens distortion parameters), constructing the dense point cloud, building the DSM, and creating the orthomosaic image. During processing, we used 98 GCPs to create the model, leaving 19 GCPs as horizontal and vertical check points. 2022-01-01T00:00:00 otherRestrictions 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. unknown This metadata was automatically generated from the FGDC Content Standard for Digital Geospatial Metadata standard (version FGDC-STD-001-1998) using the 2019-08-12T11:11:00 version of the FGDC CSDGM to ISO 19139 transform. Simone Montayne Alaska Division of Geological & Geophysical Surveys Metadata Manager (907)451-5020 (907)451-5050 3354 College Road Fairbanks AK 99709-3707 USA dggspubs@alaska.gov 8 am to 4:30 pm, Monday through Friday, except State holidays pointOfContact