{"action":"create","ckan_id":null,"date_created":"Sat, 07 Mar 2026 20:47:10 GMT","date_finished":null,"harvest_job_id":"5146f61a-f575-4df8-8eeb-1e0f3906084a","harvest_source_id":"31f41541-38a0-400b-b240-10ebcb0acd9a","id":"026bfd13-5ab9-4539-9e50-31a920263770","identifier":"https://dggs.alaska.gov/webpubs/metadata/RDF2025-8.xml","parent_identifier":null,"source_hash":"a8e8c6cd869bfe577a2891177ddc6fe4da4d68afb2f14aad02fe6c9a94637bf9","source_raw":"Zechmann, J.M.Wolken, G.J.Wikstrom Jones, K.M.2025Lidar-derived elevation data for Barry Arm, Southcentral Alaska, collected September 19, 2023dataRaw Data FileRDF 2025-8Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys9 p.https://doi.org/10.14509/31520Lidar-derived elevation data for Barry Arm, Southcentral Alaska, collected September 19, 2023, Raw Data File 2025-8, releases classified point cloud, digital terrain model (DTM), and an intensity model of Barry Arm, Southcentral Alaska, during leaf-on conditions. The survey provides snow-free surface elevations for use in landslide change detection. Aerial lidar data were collected on September 19, 2023, and ground control data were collected on August 2, 2021, and May 5, 2023, and subsequently merged and processed using a suite of geospatial processing software. This data collection is 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/10.14509/31520).The survey provides snow-free surface elevations for use in landslide change detection.>boundaries: A boundary, also known as an Area of Interest (AOI) or border, that defines the area covered by the data. Also includes footprints for tiled data.\t\r\n>classified_points: Classified point cloud data are provided in LAZ format. Data are classified following ASPRS 2019 guidelines and contain return and intensity information. For classified ground points, the average point density is 4.8 pts/m2, and the average spacing is 45.5 cm.\t\r\n>dsm: The DSM represents surface elevations, including heights of vegetation. The DSM is a single-band, 32-bit GeoTIFF file of 20-cm resolution. No Data value is set to -3.40282306074e+38 (32-bit, floating-point minimum).\t\r\n>dtm: The DTM represents bare earth elevations, excluding vegetation. The DTM is a single-band, 32-bit GeoTIFF file of 20-cm resolution. No Data value is set to -3.40282306074e+38.\t\r\n>lidar_intensity: The lidar intensity image describes the relative amplitude of reflected signals contributing to the point cloud. Lidar intensity is: (1) primarily a function of scanned object reflectance in relation to the signal frequency, (2) dependent on ambient conditions, and (3) not necessarily consistent between separate scans. The intensity image is a single-band, 32-bit GeoTIFF file of 50-cm resolution. No Data value is set to -3.40282306074e+38.2023050520230919ground conditioncompleteNone planned-148.184621-148.09144761.18125961.116887ISO 19115 Topic CategorygeoscientificInformationAlaska Division of Geological & Geophysical SurveysAerialAerial GeologyAerial PhotographyDebris AvalancheDebris FlowDGGSDigital Elevation ModelDigital Surface Model (DSM)Digital Terrain ModelElevationEngineeringEngineering GeologyGeologicGeologic HazardsGeological ProcessGeologyGeomorphologyGeotechnicalGlacialGlacial DepositsGlacial GeologyGlacial GeomorphologyGlacial ProcessesHazardsLandslideLandslide SusceptibilityLiDARPoint Cloud DataRemote SensingRock AvalancheRockfallSlopeSlope InstabilitySurfaceSurficialSurficial GeologyTopographyTsunamiUnconsolidated DepositsAlaska Division of Geological & Geophysical SurveysBarry ArmSouthcentral AlaskaThis 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).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.Alaska Division of Geological & Geophysical SurveysMetadata Managermailing and physical
3354 College Road
FairbanksAK99709-3707USA(907)451-5020(907)451-5050dggspubs@alaska.gov8 am to 4:30 pm, Monday through Friday, except State holidaysPlease 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.This work was funded by the U.S. Geological Survey grant # G21AC10362-00. We thank Clearwater Air for their expertise and contribution to these data products and Melanie Werdon for her review. The views and conclusions contained in this document are those of the authors and should not be interpreted as necessarily representing the official policies, either expressed or implied, of the U.S. Government.Stevens, D.S.P.Wolken, G.J.Hubbard, T.D.Hendricks, K.A.2018Landslides in AlaskaInformation CircularIC 65Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys2 phttps://doi.org/10.14509/29849Stevens, D.S.P.2019The Engineering Geology section at DGGSInformation CircularIC 76Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys2 phttps://doi.org/10.14509/30122Timm, KristinWolken, G.J.2017Deglacierization and the development of glacier-related hazardsInformation CircularIC 63Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys3 phttps://doi.org/10.14509/29752Wolken, G.J.Hendricks, K.A.Daanen, R.P.Overbeck, J.R.Stevens, D.S.P.Masterman, S.S.2017Alaska & climate changeInformation CircularIC 64Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys2 phttps://doi.org/10.14509/29781Not applicableDGGS visually inspected the data for errors such as shifts, seamline mismatches, and water noise overlapping land. Data quality is consistent throughout the survey, save for gaps over areas of snow or in very thick vegetation between flightlines. There was no over-collect.This is a full-release dataset.Horizontal accuracy was not measured for this collection.We measured a mean elevation offset of +46.7 cm between 35 control points and the point cloud. This offset was reduced to -1.9 cm by applying a constant vertical correction to the lidar point data. We used 34 checkpoints to determine the vertical accuracy of the point cloud ground class using a Triangulated Irregular Network (TIN) approach. The project's vertical accuracy has a root mean square error (RMSE) of 9.9 cm. We evaluated the relative accuracy for this dataset as the interswath overlap consistency and measured it at 7.0 cm RMSE.Ground survey - Ground control points were collected August 2, 2021, and May 5, 2023. For the 2021 collection, we deployed a Trimble R10-2 GNSS base receiver to provide a base station occupation and real-time kinematic (RTK) corrections to points we surveyed with a rover Trimble R10-2 GNSS receiver/Mesa controller. The ridgetop between Cascade Glacier and Barry Arm served as the base station location (cover figure). We collected 105 ground control points and checkpoints across the survey area to use for calibration and to assess the vertical accuracy of point clouds generated from multiple repeat Barry Arm surveys; 56 of these points were used for this lidar acquisition, and the remainder were excluded due to insufficient pointcloud overlap. For the 2023 collection, we deployed a Trimble R10-2 GNSS base receiver and surveyed points with a rover Trimble R10-2 GNSS receiver/Mesa controller. A bedrock island in Barry Arm served as the base station location (cover figure). We collected 130 ground control points and checkpoints across the survey area, 13 of which were used for this lidar acquisition, while the remainder were excluded due to insufficient point cloud overlap or the presence of snow at the time of the ground survey. The checkpoints and ground control points used for this lidar survey were collected on bare earth.20240720Aerial survey - DGGS used a Riegl VUX1-LR22 laser scanner with a global navigation satellite system (GNSS) and Northrop Grumman LN-200C inertial measurement unit (IMU) integrated by Phoenix LiDAR Systems. The sensor can collect a maximum of 1,500,000 points/second at a range of 230 m, or a minimum of 50,000 points/second at 1000 m (ranges assume greater than or equal to 20 percent natural reflectance). The scanner operated with a pulse refresh rate of 400,000 pulses/second at a scan rate of 130 revolutions/second. We used a Cessna 180 Skywagon fixed-wing platform to survey from an elevation of approximately 180-400 m above ground level, at a ground speed of approximately 40 m/s, and with a scan angle set from 80 to 280 degrees. The total survey area covers approximately 12.2 km2. The survey area was accessed by air during a flight from Cordova Municipal Airport to Merrill Field Airport in Anchorage. Data were collected from 5:30 pm to 6:10 pm (AKST). The weather was partly cloudy with no wind. For a base station occupation to later correct survey flightlines, we relied on data from a continuously operating GNSS station maintained by the Alaska Earthquake Center (AEC) and located on the ridgetop west of Barry Arm.20230919Dataset processing - We processed point data in Spatial Explorer for initial filtering and multiple-time-around (MTA) disambiguation. MTA errors, corrected in this process, result from ambiguous interpretations of received pulse time intervals and occur more frequently with higher pulse refresh rates. IMU and GNSS data were processed in Inertial Explorer, and flightline information was integrated with the point cloud in Spatial Explorer. We calibrated the point data at an incrementally precise scale of sensor movement and behavior, incorporating sensor velocity, roll, pitch, and yaw fluctuations throughout the survey. For the lidar data collection, the average pulse density is 9.4 pulses/m2, and the average pulse spacing is 32.7 cm. We created a macro (an ordered list of point classification commands tailored to this dataset) in Terrasolid software and classified points in accordance with the American Society for Photogrammetry & Remote Sensing (ASPRS) 2019 guidelines (ASPRS, 2019). Once classified, we applied a geometric transformation and converted the points from ellipsoidal heights to GEOID12B (Alaska) orthometric heights. Raster products were derived from the point cloud in ArcGIS Pro. A 20-cm DSM was interpolated from maximum ground and vegetation classes using a triangulation method. A 20-cm DTM was interpolated from all ground-class returns using a triangulation method and minimum values. We also produced a 50-cm intensity image using average binning in ArcGIS Pro, with no normalization or corrections applied.2024rasterUniversal Transverse Mercator60.999600-1470500000.0000000coordinate pair.00000001.00000001MetersNAD83 (2011)GRS 806378137298.257222101NAVD88, GEOID12B0.500000metersExplicit elevation coordinate included with horizontal coordinatesboundariesA boundary, also known as an Area of Interest (AOI) or border, that defines the area covered by the data. Also includes footprints for tiled data.DGGSboundariesclassified_pointsClassified point cloud data are provided in LAZ format. Data are classified following ASPRS 2019 guidelines and contain return and intensity information. For classified ground points, the average point density is 4.8 pts/m2, and the average spacing is 45.5 cm.DGGSclassified_pointsdsmThe DSM represents surface elevations, including heights of vegetation. The DSM is a single-band, 32-bit GeoTIFF file of 20-cm resolution. No Data value is set to -3.40282306074e+38 (32-bit, floating-point minimum).DGGSdsmdtmThe DTM represents bare earth elevations, excluding vegetation. The DTM is a single-band, 32-bit GeoTIFF file of 20-cm resolution. No Data value is set to -3.40282306074e+38.DGGSdtmlidar_intensityThe lidar intensity image describes the relative amplitude of reflected signals contributing to the point cloud. Lidar intensity is: (1) primarily a function of scanned object reflectance in relation to the signal frequency, (2) dependent on ambient conditions, and (3) not necessarily consistent between separate scans. The intensity image is a single-band, 32-bit GeoTIFF file of 50-cm resolution. No Data value is set to -3.40282306074e+38.DGGSlidar_intensityAlaska Division of Geological & Geophysical SurveysMetadata Managermailing and physical
3354 College Road
FairbanksAK99709-3707USA(907)451-5020(907)451-5050dggspubs@alaska.gov8 am to 4:30 pm, Monday through Friday, except State holidaysPlease 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.RDF 2025-8The 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.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.Contact DGGS for current pricingdata20250626boundaries, classified points, dsm, dtm and lidar intensityhttps://doi.org/10.14509/31520Free download20250626Alaska Division of Geological & Geophysical SurveysSimone MontayneMetadata Managermailing and physical
3354 College Road
FairbanksAK99709-3707USA(907)451-5020(907)451-5050dggspubs@alaska.gov8 am to 4:30 pm, Monday through Friday, except State holidaysFGDC Content Standard for Digital Geospatial MetadataFGDC-STD-001-1998If 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.https://dggs.alaska.gov/metadata/dggs.extdggs metadata extensions","source_transform":null,"status":"error"}