{"action":"create","ckan_id":null,"date_created":"Wed, 18 Mar 2026 06:21:54 GMT","date_finished":null,"harvest_job_id":"1e284e2c-942c-40e1-a831-c420bda7948f","harvest_source_id":"f4c7bbab-c7ef-4277-a7d3-c25b78854814","id":"515c6a9c-cf8f-40ba-ad4f-a9e1bba2f50c","identifier":"https://dggs.alaska.gov/webpubs/metadata/RDF2023-2.xml","parent_identifier":null,"source_hash":"9ed4b9b890ffbb4643b6c4d01b9b2ec1a89e5e0fd15083d3a182b39d4a6c8a0b","source_raw":"Zechmann, J.M.Wikstrom Jones, KatreenWolken, G.J.2023Lidar-derived elevation data for land near Grewingk Glacier and Halibut Cove Lagoon, Southcentral Alaska, collected October 12-13, 2021dataRaw Data FileRDF 2023-2Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys11 p.https://doi.org/10.14509/30958Lidar-derived elevation data for land near Grewingk Glacier and Halibut Cove Lagoon, Southcentral Alaska, collected October 12-13, 2021, Raw Data File 2023-2, uses aerial lidar to produce a classified point cloud, digital surface model (DSM), digital terrain models (DTM), and intensity model of land near Grewingk Glacier and Halibut Cove Lagoon, located in Southcentral Alaska (cover figure). Aerial data were collected October 12-13, 2021, and subsequently processed in a suite of geospatial processing software. Ground control data were collected on October 12, 2021. This data supports a paraglacial rock slope destabilization study at Grewingk Glacier and Grewingk Lake and will be used to assess and characterize an ongoing landslide hazard. All files can be downloaded from the Alaska Division of Geological & Geophysical Surveys website (http://doi.org/10.14509/30958).This data supports a paraglacial rock slope destabilization study at Grewingk Glacier and Grewingk Lake and will be used to assess and characterize an ongoing landslide hazard.>classified_points: Classified point cloud data are provided in compressed LAZ format. Data are classified in accordance with ASPRS 2019 guidelines (table 1) and contain return and intensity information. For ground points, the average pulse spacing is 52 cm, and the average point density is 3.69 pts/m2.\t\r\n>dsm: The DSM represents surface elevations, including heights of vegetation, buildings, powerlines, etc. The DSM is a single-band, 32-bit GeoTIFF file of 1-meter resolution. No Data value is set to -3.40282306074e+38 (32-bit, floating-point minimum).\t\r\n>dtm: The DTM represent bare earth elevations, excluding vegetation, bridges, buildings, etc. the DTM is single-band, 32-bit float GeoTIFF file, of 1-meter resolution. No Data value is set to -9999.\t\r\n>dtm_detail: The detailed DTM represents bare earth elevations, excluding vegetation. The DTM is single-band, 32-bit float GeoTIFF file, of 20-cm resolution. This higher-resolution DTM file covers an area identified as a scientific priority. No Data value is set to -9999.\t\r\n>lidar_intensity: The lidar intensity image depicts the relative amplitude of reflected signals contributing to the point cloud. Lidar intensity is primarily a function of scanned object reflectance in relation to the signal frequency, is dependent on ambient conditions, and is not necessarily consistent between separate scans. The intensity image is a single-band, 32-bit float GeoTIFF file of 1-meter resolution. No Data value is set to -3.40282306074e+38.\t\r\n>lidar_las_index: The LAS index file is a shapefile with polygons that serve as an index to the spatial location and extent of each point cloud (LAS) bin.2022101220221013ground conditioncompleteNone planned-151.232799-150.92840559.69149859.493974ISO 19115 Topic CategorygeoscientificInformationAlaska Division of Geological & Geophysical SurveysAerialAerial GeologyDGGSDigital Elevation ModelDigital Surface Model (DSM)ElevationEnvironmentalGeomorphologyGeotechnicalGlacial GeologyGlacial GeomorphologyGlacial ProcessesGlaciersGlaciologyHazardsHydrology and Surficial GeologyLandslideLiDARLiDAR Intensity ImagePeriglacial Slope FailurePoint Cloud DataPoint CountSlopeSlope InstabilityAlaska Division of Geological & Geophysical SurveysChina Poot LakeCook InletGlacier SpitGrewingk CreekGrewingk GlacierHalibut CoveHalibut CreekHomerHumpy CreekKachemak BayKachemak Bay State ParkQuiet CreekSouthcentral AlaskaWalker, J.D., Geissman, J.W., Bowring, S.A, and Babcock, L.E., comp., 2012, Geologic Time Scale v. 4.0: Geological Society of AmericaHoloceneThis 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.The area of this survey is on the traditional homelands of the Dena'ina people. These data products were funded by RWTH-Aachen University through a grant from the German Research Foundation and the State of Alaska and collected and processed by DGGS. We are grateful to Bretwood 'Hig' Higman for assistance with ground-based surveying. We also thank Clearwater Air for their aviation expertise and contribution to these data products. 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.Salisbury, J.B.Daanen, R.P.Herbst, A.M.2021Lidar-derived elevation models for Homer, AlaskaRaw Data FileRDF 2021-2Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys6 phttps://doi.org/10.14509/30591Salisbury, J.B.Herbst, A.M.Daanen, R.P.2021Lidar-derived elevation models for the Grewingk Glacier 1967 landslide scar, Alaska, collected June 3, 2019Raw Data FileRDF 2021-6Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys7 phttps://doi.org/10.14509/30599Not applicableThis is a complete release dataset. There was no over-collect except for aircraft turns that were eliminated from the dataset. The data quality is consistent throughout the survey, save for two small (~0.1 km2) data gaps located along Halibut Creek and in the southeast corner of the study area.This data relaease is complete.We did not measure horizontal accuracy for this collection.We achieved a vertical accuracy of 3.9 cm average magnitude offset between the lidar point cloud and 178 ground control points by performing a rubbersheet correction. In addition, we evaluated the relative accuracy for this dataset as the interswath overlap consistency and measured it at 8.0 cm RMSE.Aerial photogrammetric survey - DGGS used a Riegl VUX1-LR laser scanner integrated with a global navigation satellite system (GNSS) and Northrop Grumman LN-200C inertial measurement unit (IMU). The lidar integration system was designed by Phoenix LiDAR Systems. The sensor can collect up to 820,000 points per second at a range of up to 150 m. The scanner operated with a pulse refresh rate of 100,000 pulses per second in alpine areas and up to 600,000 pulses per second over forested areas at a scan rate between 100 and 200 lines per second. We used a Cessna 180 fixed-wing platform to survey from an elevation of ~100-500 m above ground level, at a ground speed of ~37 m/s, and with a scan angle set from 80 to 280 degrees. The total survey area covers ~145 km2. On October 12, we departed Homer Airport at 1:20 pm and covered the Grewingk valley from Kachemak Bay to the lower Grewingk Glacier (fig. 1). We landed back at Homer Airport at 4:15 pm. On October 13, we departed Homer Airport at 10:00 am and covered a swath from Halibut Cove and lower Halibut Creek south to the river that drains Wosnesenski Glacier. Our return time to Homer Airport was 1:30 pm. The weather throughout the survey was partly cloudy to overcast.20221013Ground survey - We collected ground control and checkpoints on October 12, 2021. We deployed a Trimble R10-2 GNSS receiver with an internal antenna at a temporary benchmark on the Grewingk Glacier fan delta (59 degrees 38 minutes 27.39 seconds N; 151 degrees 12 minutes 13.338 seconds W). It provided a base station occupation and real-time kinematic (RTK) corrections to points we surveyed with a rover Trimble R10-2 GNSS receiver (internal antenna). We collected a total of 178 ground control and checkpoints for calibration and to assess the vertical accuracy of the point cloud. All points were collected on bare earth.20221012Lidar dataset processing - We processed point data in SDCimport software 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. We processed Inertial Measurement Unit (IMU) and Global Navigation Satellite System (GNSS) data in Inertial Explorer, and we used Spatial Explorer software to integrate flightline information with the point cloud. 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. We created macros in Terrasolid software and classified points in accordance with American Society for Photogrammetry and Remote Sensing (ASPRS) 2019 guidelines. Once classified, we applied a geometric transformation and converted the points from ellipsoidal heights to GEOID12B (Alaska) orthometric heights.\r\nWe used ArcGIS Pro to derive raster products from the point cloud. The DSM was interpolated from maximum return values from the ground, vegetation, and building classes using a binning method. The 1-meter DTM was interpolated from all ground class returns, also using a binning method and minimum values. An additional 20-cm DTM encompassing the northern part of the study area (dashed line in cover image) was produced using triangulation with natural neighbor interpolation. In ArcGIS Pro, we created a 1-meter intensity image by binning and averaging ground, vegetation, and building classes. Using the ArcGIS Pro Pixel Editor, we hydroflattened both DTMs and the DSM. Water surface elevations were preserved where possible, and interpolation artifacts were replaced with average water surface elevations and smoothed using the Pixel Editor blur tool.2022rasterUniversal Transverse Mercator50.999600-1530500000.0000000coordinate pair.00000001.00000001MetersNAD83 (2011)GRS 806378137298.257222101NAVD88, GEOID12B0.001metersExplicit elevation coordinate included with horizontal coordinatesclassified_pointsClassified point cloud data are provided in compressed LAZ format. Data are classified in accordance with ASPRS 2019 guidelines (table 1) and contain return and intensity information. For ground points, the average pulse spacing is 52 cm, and the average point density is 3.69 pts/m2.DGGSclassified_pointsdsmThe DSM represents surface elevations, including heights of vegetation, buildings, powerlines, etc. The DSM is a single-band, 32-bit GeoTIFF file of 1-meter resolution. No Data value is set to -3.40282306074e+38 (32-bit, floating-point minimum).DGGSdsmdtmThe DTM represent bare earth elevations, excluding vegetation, bridges, buildings, etc. the DTM is single-band, 32-bit float GeoTIFF file, of 1-meter resolution. No Data value is set to -9999.DGGSdtmdtm_detailThe detailed DTM represents bare earth elevations, excluding vegetation. The DTM is single-band, 32-bit float GeoTIFF file, of 20-cm resolution. This higher-resolution DTM file covers an area identified as a scientific priority. No Data value is set to -9999.DGGSdtm_detaillidar_intensityThe lidar intensity image depicts the relative amplitude of reflected signals contributing to the point cloud. Lidar intensity is primarily a function of scanned object reflectance in relation to the signal frequency, is dependent on ambient conditions, and is not necessarily consistent between separate scans. The intensity image is a single-band, 32-bit float GeoTIFF file of 1-meter resolution. No Data value is set to -3.40282306074e+38.DGGSlidar_intensitylidar_las_indexThe LAS index file is a shapefile with polygons that serve as an index to the spatial location and extent of each point cloud (LAS) bin.DGGSlidar_las_indexAlaska 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 2023-2The 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 pricingdata20230406classified points, dsm, dtm, dtm detail, lidar intensity and lidar las indexhttps://doi.org/10.14509/30958Free download20230406Alaska 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"}