dda04a1f-695c-476e-bce7-9bdbf584aa60_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 2019-12-06 ISO 19115 Geographic Information - Metadata ISO 19115:2003/Cor.1:2006(E) High-resolution lidar data for the Chilkat Ridge area, Alaska 2019-01-01 publication Alaska Division of Geological & Geophysical Surveys Fairbanks Alaska, United States publisher Daanen, R.D. originator Wikstrom Jones, Katreen originator http://doi.org/10.14509/30224 DIGITAL DATA Raw Data File RDF 2019-7 11 p. The 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. This 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. These 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. 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 pointOfContact notPlanned Aerial Geology Bare-Earth Digital Elevation Model (DEM) Coastal and River Digital Elevation Model Digital Surface Model (DSM) Elevation Engineering Engineering Geology Geomorphology Geospatial Accuracy Geotechnical LiDAR LiDAR Intensity Image Point Cloud Data Raster Image Remote Sensing Surface Surficial Vegetation Web Service theme Alaska Division of Geological & Geophysical Surveys Anman Creek Birch Island Chilkat Chilkat Lake Chilkat River Chilkat River State Critical Habitat Area Dalton Trail Juneau Mining District Kicking Horse River Klehini River Kohklux Porcupine Creek Mining District Southeast Alaska Takhin River Tsirku River 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). vector eng; USA geoscientificInformation -135.970710 -135.640466 59.236685 59.414268 2018-01-01 2019-01-01 >point_cloud_data: Classified (ASPRS standard) lidar values for all returns; File format: LAS 1.4. >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. >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. >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. true Classified point cloud data, digital surface model, digital terrain model, and intensity image 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 distributor Contact DGGS for current pricing Free download http://doi.org/10.14509/30224 Classified point cloud data, digital surface model, digital terrain model, and intensity image CSDGM IMPORT ERROR: No digtinfo/formcont information dataset Horizontal Positional Accuracy Report Horizontal accuracy was not evaluated for this project. Vertical Positional Accuracy Report The 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. The 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. The 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. To 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. This lineage was generated by the FGDC CSDGM to 19139 transformation Lidar 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. 2018-01-01T00:00:00 Raw 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. 2018-01-01T00:00:00 Point 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. 2018-01-01T00:00:00 Point 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. 2018-01-01T00:00:00 Digital 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. 2019-01-01T00:00:00 Digital 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. 2019-01-01T00:00:00 Intensity image - The intensity raster was generated using the ground points. The raster resolution is 1-meter. 2019-01-01T00:00:00 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