1fc9c212-14b8-4663-a8c8-60247545c909_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 2021-01-22 ISO 19115 Geographic Information - Metadata ISO 19115:2003/Cor.1:2006(E) Lidar-derived elevation data for Turnagain Pass, southcentral Alaska, September 2, 2018 2021-01-01 publication Alaska Division of Geological & Geophysical Surveys Fairbanks Alaska, United States publisher Wikstrom Jones, Katreen originator Wolken, G.J. originator Daanen, R.P. originator Herbst, A.M. originator https://doi.org/10.14509/30567 REPORT, POINT CLOUD, GEOTIFF Raw Data File RDF 2020-16 7 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) of Turnagain Pass, southcentral Alaska, during snow-free ground conditions. This dataset includes point cloud data, a 32-bit digital terrain model and digital surface model, and an intensity image covering Turnagain Pass located southeast of Anchorage within the Chugach National Forest on the Kenai Peninsula in southcentral Alaska. The lidar and Global Navigation Satellite System (GNSS) data were collected on September 2, 2018, and processed using Terrasolid. This data collection is released as a Raw Data File with an open end-user license. All files can be downloaded free of charge from the Alaska Division of Geological & Geophysical Surveys website: http://doi.org/10.14509/30567 The goal of the survey is to provide snow-free surface elevations for deriving snow depth distribution models with repeat surveys during snow-covered surface conditions. This data release is one of a series of DGGS publications to present elevation data. These data products were funded by U.S. Geological Surveys and Alaska Department of Natural Resources, Division of Geological & Geophysical Surveys. We thank Clearwater Air 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 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 Digital Elevation Model Digital Surface Model (DSM) Engineering Engineering Geology Geologic Geology Geomorphology Geotechnical LiDAR Point Cloud Data Remote Sensing Surficial Surficial Geology Topography Web Service theme Alaska Division of Geological & Geophysical Surveys Bench Creek Bertha Creek Center Creek East Fork Sixmile Creek Granite Creek Ingram Creek Kickstep Mountain Lynx Creek Lyon Creek Petes Creek Spokane Creek Taylor Creek Tincan Creek Tincan Peak Turnagain Arm Turnagain Pass Wolverine Creek 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). Inventory and preliminary assessment of geologic hazards in the Passage Canal-Portage Valley area, south-central Alaska 2014-01-01 publication Alaska Division of Geological & Geophysical Surveys Fairbanks Alaska, United States publisher Wolken, G.J. originator Balazs, M.S. originator https://doi.org/10.14509/27302 Preliminary Interpretive Report PIR 2014-1 15 p crossReference Alaska & climate change 2017-01-01 publication Alaska Division of Geological & Geophysical Surveys Fairbanks Alaska, United States publisher Wolken, G.J. originator Hendricks, K.A. originator Daanen, R.P. originator Overbeck, J.R. originator Stevens, D.S.P. originator Masterman, S.S. originator https://doi.org/10.14509/29781 Information Circular IC 64 2 p crossReference grid eng; USA geoscientificInformation -149.331846 -149.022184 60.707115 60.866217 2018-09-02 >classified point cloud data: The ground-classified point cloud has an average point spacing of 43 cm (43 cm on the ground in open alpine areas and 32 cm below dense vegetation in the valley) and an average point density of 2.3 points per square meter. >digital surface model: The DSM represents surface elevations, for example heights of vegetation, buildings, bridges, etc. The DSM is a single band, 32-bit GeoTIFF file, with a ground sample distance of 50 cm. No Data value is set to -3.40282306074e+038. >digital terrain model: The DTM represents elevations of ground surfaces, excluding vegetation, bridges, buildings, etc. The DTM is a single-band, 32-bit float GeoTIFF file, with a ground sample distance of 50 cm. No Data value is set to -3.40282306074e+038. >lidar intensity image: The intensity image represents the return strengths of the first return laser pulses. The intensity image is a single band, 32-bit GeoTIFF file, with a ground sample distance of 50 centimeter and normalized to the 0-255 range. No Data value is set to -3.40282306074e+038. true report, point-cloud, GeoTIFF 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/10.14509/30567 report, point-cloud, GeoTIFF classified point cloud data, digital surface model, digital terrain model, and lidar intensity image information dataset Horizontal Positional Accuracy Report Horizontal accuracy was not measured for this collection. Vertical Positional Accuracy Report The elevation values of 62 ground control points were compared with the elevation values of the lidar points classified as ground points. The average vertical offset was corrected with a z-transformation. 15 check points were used to determine the final accuracy of the z-transformed lidar point cloud. The lidar point cloud had a vertical offset of +2.2 cm (root mean squared error [RMSE] 3.6 cm) compared to ground control, therefore a vertical transformation of -2.2 cm was applied to the lidar point cloud. The final accuracy assessment showed a mean vertical offset of -0.3 cm and RMSE of 3.3 cm. Relative accuracy for this dataset was evaluated as the interswath overlap consistency and was measured at 1.2 cm RMSE. 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 laser range exceedance, which is related to the slow response of the fixed wing aircraft to the fast elevation change along the flight path. All low points and air points were eliminated from the dataset. 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 laser range exceedance, which is related to the slow response of the fixed wing aircraft to the fast elevation change along the flight path. All low points and air points were eliminated from the dataset. Relative accuracy for this dataset was evaluated as the interswath overlap consistency and was measured at 1.2 cm RMSE. This lineage was generated by the FGDC CSDGM to 19139 transformation Airborne survey - This lidar survey was flown at an average elevation of 200 m above ground level and a ground speed of approximately 40 meters per second with a fixed-wing Cessna 180. Elevation data were acquired with a Riegl VUX1-LR laser scanner integrated with a GNSS and Northrop Grumman IMU system. The integration was designed by Phoenix LiDAR systems. Lidar data were acquired at a pulse rate ranging from 50,000 pulses per second in the alpine areas to 400,000 pulses per second over forested areas, a scan rate of 200 revolutions per second, and a scan angle range of 80-280 degrees. The accompanying report provides additional detail regarding flight conditions. 2018-09-02T00:00:00 Ground survey - Ground control and check points were collected on September 2, 2018. A Trimble R7 GNSS receiver with Zephyr-2 antenna was deployed near the center of the study area and provided a base station occupation and real-time kinematic (RTK) corrections to points surveyed with a rover Trimble R8-4 GNSS receiver (internal antenna). 78 total ground control points and check points were collected to be used for calibration and assessment of the vertical accuracy of the point cloud. All points were collected on a paved road surface. 2018-09-02T00:00:00 Lidar dataset 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 GNSS and IMU data are integrated to establish correct flight path and orientation of the lidar sensor. Internal consistency of the dataset was improved by calibrating the point cloud data using global, flight line, and fluctuation (within individual flightlines) tielines in Terrasolid software. The point cloud was classified for ground points as well as low, medium, and high vegetation (0.01-0.5 m, 0.5-3 m, and 3-60 m heights above the ground, respectively, in accordance with ASPRS lidar classification codes). Some manual processing was required to eliminate erratically placed points and misclassified ground points. All low points and air points were eliminated from the dataset. A LAS dataset was created in ArcMAP, from which a 50 cm DTM, DSM, and intensity image were produced. The DTM was derived from elevation values of ground-classified points only, and built using the binning technique of minimum elevation and linear void fill. The DSM was derived from elevation values from first returns from all point classes, and built using the binning technique of average elevation values and linear void fill. The intensity image was derived from intensity values of first return points. 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