{"action":"create","ckan_id":null,"date_created":"Sat, 28 Mar 2026 21:11:39 GMT","date_finished":null,"harvest_job_id":"c87df6d4-55a4-4157-8f97-1f84fe294e8c","harvest_source_id":"31f41541-38a0-400b-b240-10ebcb0acd9a","id":"b7e1fe52-8908-4dbf-bd06-6dd76197f0f4","identifier":"https://dggs.alaska.gov/webpubs/metadata/RDF2019-7.xml","parent_identifier":null,"source_hash":"ee43105ff80852f237354f27e9793401b20005c71ec08140302f1d131c072017","source_raw":"\n\n\n\n\nDaanen, R.D.\nWikstrom Jones, Katreen\n2019\nHigh-resolution lidar data for the Chilkat Ridge area, Alaska\ndigital data\n\nRaw Data File\nRDF 2019-7\n\n\nFairbanks, Alaska, United States\nAlaska Division of Geological & Geophysical Surveys\n\n11 p.\nhttp://doi.org/10.14509/30224\n\n\n\nThe State of Alaska Division of Geological & Geophysical Surveys (DGGS) used lidar to produce a digital terrain model (DTM) and digital surface model (DSM) over ridgelines along the Chilkat River just north of Haines, Alaska. The lidar and Global Navigation Satellite System (GNSS) data were collected on November 15-16, 2018, and processed using Terrasolid. This data collection is being released as a Raw Data File with an open end-user license. The complete report and digital data are available from the DGGS website: http://doi.org/10.14509/30224.\nThis dataset includes point cloud data, a 32-bit digital terrain model, and an intensity image covering a study area near the Chilkat Ridge region of southeast Alaska. The data release is one of a series of Alaska Division of Geological & Geophysical Surveys (DGGS) publications to present elevation data. The goal is to provide information for the Alaska Division of Forestry on the ground conditions and tree cover on Chilkat Ridge.\n\n>point_cloud_data: Classified (ASPRS standard) lidar values for all returns; File format: LAS 1.4.\t\n>dtm: DTMs represent surface elevations of ground surfaces, excluding vegetation, bridges, buildings, etc. The DTM is a single-band, 1 meter, 32-bit float GeoTIFF file, with a ground sample distance (GSD) of 15 cm on the ground and 60 cm below dense vegetation. No Data value is set to -3.40282306074e+038.\t\n>dsm: A 2-meter DSM raster was created from the first returns of the laser point cloud. The No Data value is set to -3.40282306074e+038.\t\n>intensity_image: A grayscale image that displays 0-255 grayscale values according to relative reflectivity. The laser intensity image is provided as a 1-meter raster.\n\n\n\n\n\n2018\n2019\n\n\nground condition\n\n\ncomplete\nNone planned\n\n\n\n-135.970710\n-135.640466\n59.414268\n59.236685\n\n\n\n\nISO 19115 Topic Category\ngeoscientificInformation\n\n\nAlaska Division of Geological & Geophysical Surveys\nAerial Geology\nBare-Earth Digital Elevation Model (DEM)\nCoastal and River\nDigital Elevation Model\nDigital Surface Model (DSM)\nElevation\nEngineering\nEngineering Geology\nGeomorphology\nGeospatial Accuracy\nGeotechnical\nLiDAR\nLiDAR Intensity Image\nPoint Cloud Data\nRaster Image\nRemote Sensing\nSurface\nSurficial\nVegetation\nWeb Service\n\n\nAlaska Division of Geological & Geophysical Surveys\nAnman Creek\nBirch Island\nChilkat\nChilkat Lake\nChilkat River\nChilkat River State Critical Habitat Area\nDalton Trail\nJuneau Mining District\nKicking Horse River\nKlehini River\nKohklux\nPorcupine Creek Mining District\nSoutheast Alaska\nTakhin River\nTsirku River\n\n\nThis 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).\nAny 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.\n\n\n\nAlaska Division of Geological & Geophysical Surveys\n\nMetadata Manager\n\nmailing and physical\n
3354 College Road
\nFairbanks\nAK\n99709-3707\nUSA\n\n(907)451-5020\n(907)451-5050\ndggspubs@alaska.gov\n8 am to 4:30 pm, Monday through Friday, except State holidays\n\n\nThese data products were funded by the Alaska Division of Forestry. We thank Clearwater Air from Anchorage for their aviation expertise and contribution to these data products.\n\n\n\nSurveyed ground control, captured with a Trimble RTK GPS, provided both control points, to be used in calibration, and checkpoints, to be used in the accuracy assessment of the lidar point cloud. A snow crust was observed on most ground surfaces but was less than 5 cm thick and highly variable. This crust of snow is not expected to affect the elevation map beyond the overall accuracy capability of the survey. All points collected were in natural terrain with variable amounts of vegetated cover. See accompanying project report for additional discussion and a complete listing of checkpoints and control points.\n\nTo evaluate data consistency, ground checkpoints were collected (November 15, 2018) as RTK-GNSS points with a Trimble R8 GNSS receiver. A Trimble R7 GNSS receiver with Zephyr-2 antenna was deployed near the center of the study area and was used as horizontal and vertical control for checkpoint baseline corrections. The checkpoints were compared with the DTM. The comparison showed a 7.1 cm average magnitude difference between the checkpoints and the DTM. The checkpoint differences had a Root Mean Square Error of 8.5 cm and a standard deviation of 8.6 cm.\nThe total area surveyed was approximately 224 km2. This data release is complete and there is no over-collect, except for the aircraft turns that were eliminated from the dataset. There are a few areas where data coverage is limited due to the slow response of the fixed wing aircraft the fast elevation changes along the flight path, e.g., canyons. Void areas for lakes and ponds, which were hydroflattened in the elevation models, were delineated as null data in the intensity rasters.\n\n\nHorizontal accuracy was not evaluated for this project.\n\n\nThe Root Mean Square Error of the final data layers for the bare earth elevation between the checkpoints and lidar ground points is 8.5 centimeters.\n\n\n\n\nLidar data acquisition - DGGS operates a Riegle VUX1-LR lidar integrated with a GNSS and Northrop Grumman IMU system. The integration was designed by Phoenix LiDAR systems. The sensor is capable of collecting up to 820,000 points per second over a distance of 150 m. This survey was flown at a scan rate of 400,000 points per second and a scan rate of 200 revolutions per second. The average pulse spacing was 15 cm and the average point density was 40 points per square meter. This survey was flown with an average elevation of 200 m above ground level and a ground speed of approximately 40 m/s with a fixed-wing aircraft configuration, using Cessna 185. The scan angle was set from 55 to 305. Ground Control points were collected using a Trimble system consisting of a Trimble R7 base station and an R8 rover system.\n2018\n\n\nRaw lidar data processing - Raw data were processed using Terrasolid software to produce integrated files for navigation correction and a point cloud for calibration. The navigation was corrected using Inertial Explorer software, where the GNNS and IMU data are integrated to establish the correct flight path and orientation of the lidar sensor.\n2018\n\n\nPoint cloud data calibration - Internal lidar point cloud data were calibrated using Terrasolid software. The initial accuracy of the point cloud was 8.346 cm. After calibration, the point cloud had an average magnitude accuracy of 6.914 cm.\n2018\n\n\nPoint cloud data classification - The point cloud is classified for ground points as well as low, medium, and high vegetation (0.01-0.3 m, 0.3-5 m, and 5-60 m heights above the ground, respectively). Some manual processing was required to eliminate fog and misclassified ground points. All low points and air points are eliminated from the dataset. Lastly, the DSM and DTM were hydroflattened to mean surrounding elevation for all lakes and ponds.\n2018\n\n\nDigital terrain model - The ground points from the final point cloud were used to build the digital terrain model in ArcGIS. The point cloud was loaded as a las dataset and filtered for ground points. The remaining points were used in a las dataset-to-raster conversion tool. Rasters, with a ground pixel resolution of 1 meter, were derived from mean values from a 2-meter sampling distance. The DTM was hydroflattened to mean surrounding elevation for all lakes and ponds.\n2019\n\n\nDigital surface model - The digital surface model was created from the first returns in the point cloud. Due to a large number of points in vegetation, we used a binning method with natural neighbor gap-filling. The 1 m bins did not gap-fill correctly in the entire dataset, however, so we opted to store the DSM in a 2-m-resolution raster. The DSM was hydroflattened to mean surrounding elevation for all lakes and ponds.\n2019\n\n\nIntensity image - The intensity raster was generated using the ground points. The raster resolution is 1-meter.\n2019\n\n\n\n\npoint\n\n\n\n\n\nUniversal Transverse Mercator\n\n8\n\n0.999600\n-135\n0\n500000.000000\n0\n\n\n\n\ncoordinate pair\n\n.00000001\n.00000001\n\nMeters\n\n\n\nNorth American Datum of 1983\nGRS 80\n6378137\n298.257222101000025\n\n\n\n\nNAVD88; GEOID12B\n1\nmeter\nImplicit coordinate\n\n\n\n\n\n\npoint_cloud_data\nClassified (ASPRS standard) lidar values for all returns; File format: LAS 1.4.\nAlaska Division of Geological & Geophysical Surveys (DGGS)\npoint_cloud_data\n\n\n\n\ndtm\nDTMs represent surface elevations of ground surfaces, excluding vegetation, bridges, buildings, etc. The DTM is a single-band, 1 meter, 32-bit float GeoTIFF file, with a ground sample distance (GSD) of 15 cm on the ground and 60 cm below dense vegetation. No Data value is set to -3.40282306074e+038.\nAlaska Division of Geological & Geophysical Surveys (DGGS)\ndtm\n\n\n\n\ndsm\nA 2-meter DSM raster was created from the first returns of the laser point cloud. The No Data value is set to -3.40282306074e+038.\nAlaska Division of Geological & Geophysical Surveys (DGGS)\ndsm\n\n\n\n\nintensity_image\nA grayscale image that displays 0-255 grayscale values according to relative reflectivity. The laser intensity image is provided as a 1-meter raster.\nAlaska Division of Geological & Geophysical Surveys (DGGS)\nintensity_image\n\n\n\n\n\n\n\nAlaska Division of Geological & Geophysical Surveys\n\nMetadata Manager\n\nmailing and physical\n
3354 College Road
\nFairbanks\nAK\n99709-3707\nUSA\n\n(907)451-5020\n(907)451-5050\ndggspubs@alaska.gov\n8 am to 4:30 pm, Monday through Friday, except State holidays\n\n\nRDF 2019-7\nThe 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.\n\nDGGS 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.\nContact DGGS for current pricing\n\n\n\n\nClassified point cloud data, digital surface model, digital terrain model, and intensity image\n\n\n\n\n\nhttp://doi.org/10.14509/30224\n\n\n\n\n\nFree download\n\n\n\n20191206\n\n\n\nAlaska Division of Geological & Geophysical Surveys\nSimone Montayne\n\nMetadata Manager\n\nmailing and physical\n
3354 College Road
\nFairbanks\nAK\n99709-3707\nUSA\n\n(907)451-5020\n(907)451-5050\ndggspubs@alaska.gov\n8 am to 4:30 pm, Monday through Friday, except State holidays\n\n\nFGDC Content Standard for Digital Geospatial Metadata\nFGDC-STD-001-1998\nIf 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.\n\nhttp://www.dggs.alaska.gov/metadata/dggs.ext\ndggs metadata extensions\n\n\n\n","source_transform":null,"status":"error"}