boundaries: A boundary, also known as an Area of Interest (AOI) or border, that defines the area covered by the data. classified_points: Classified point cloud data are provided in LAS format. Data are classified following ASPRS 2019 guidelines and contain return and intensity information. For all ground points, the average point spacing is 57.0 cm, and the average density is 3.08 pts/m2. For the 2021 Iron Mountain closeup, the average ground point spacing is 36.4 cm, and the average ground point density is 7.54 pts/m2; for the Iron Mountain 2022 dataset, the average ground point spacing is 58.2 cm, and the average ground point density is 2.95 pts/m2. The Beach Road 2021 closeup has an average ground point spacing of 36.8 cm and an average ground point density of 7.37 pts/m2; for the 2022 Beach Road closeup the average ground point spacing and density were 50.3 cm and 3.95 pts/m2, respectively. Includes a shapefile index of the spatial location and extent of each point cloud (LAS) bin. dsm: The DSM represents surface elevations, including heights of vegetation, buildings, powerlines, etc. The DSM is a single-band, 32-bit GeoTIFF file of 50-centimeter resolution. No Data value is set to -3.40282306074e+38 (32-bit, floating-point minimum). dtm: The DTMs represent bare earth elevations, excluding vegetation, bridges, buildings, etc. We produced five DTMs, one 50-cm DTM named DTM and four 20-cm DTMs named DTM_detail_iron_mountain_2021, DTM_detail_iron_mountain_2022, DTM_detail_beach _road_2021, and DTM_detail_beach_road_2022. All DTMs are single-band, 32-bit float GeoTIFF files. The higher-resolution DTMs were identified as areas of significant ground surface elevation change between October 2021 and October 2022. No Data value is set to -3.40282306074e+38. lidar_intensity: The lidar intensity image describes 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, 16-bit unsigned GeoTIFF file of 0.5-meter resolution. No Data value is set to -3.40282306074e+38.
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This survey area is on the traditional homelands of the Tlingit people. This project was funded by the Federal Emergency Management Agency grant number EMS-2021-CA-00013. We thank Coastal Helicopters for their aviation expertise and contribution to these data products, and the Alaska Division of Mining, Land and Water for providing ground control points. Additionally, we thank Greg Palmeri of the Alaska Division of Forestry & Fire Protection for his help selecting survey area priorities. 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.
The survey provides snow-free surface elevations for assessing landslide hazards and, in two active slide areas, elevation changes between October 2021 and October 2022.
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Are there legal restrictions on access or use of the data?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).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.
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.
| Data format: | boundaries, classified points, dsm, dtm and lidar intensity in format data |
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https://doi.org/10.14509/31034 |