classified point cloud data: Classified point cloud data is provided in this collection in compressed *.LAZ format. Data are classified in accordance with ASPRS 2014 guidelines and contain return and intensity information. The average point spacing is 54.07 cm, and the average point density is 3.42 points per square meter. Elevation surfaces interpolated from areas with a point density of fewer than 2 pts/m2 were designated as "low confidence areas" rather than classified as No Data. This decision was made to preserve the visual consistency of the data while remaining forthright about its quality. digital surface model: The DSM represents surface elevations as they appear to the naked eye, including the heights of vegetation, buildings, bridges, etc. The DSM is a single band, 32-bit GeoTIFF file, with a ground sample distance of 0.5 meters. No Data value is set to -3.40282306074e+038. digital terrain model: The DTM represents surface elevations of ground surfaces, achieved by penetrating or flattening any vegetation, bridges, buildings, and other non-ground features. The DTM is a single-band, 32-bit float GeoTIFF file with a ground sample distance of 0.5 meters. No Data value is set to -3.40282306074e+038 (the 32-bit, floating-point minimum). hydro-flattened digital terrain model: The hydro-flattened DTM represents bare earth surfaces that have undergone a selective "flattening" process, where elevation values for any hydrologic features are replaced with a consistent, appropriate pixel (elevation) value. The hydro-enforced DTM is a single-band, 32-bit float GeoTIFF file with a ground sample distance of 0.5 meters. No Data value is set to -3.40282306074e+038. lidar intensity image: The lidar intensity image describes the relative amplitude of reflected signals contributing to the point cloud. Lidar intensity is largely 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 with a ground sample distance of 0.5 meters. No Data value is set to -3.40282306074e+038.
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These data products were funded by the State of Alaska and collected and processed by Alaska Division of Geological & Geophysical Surveys staff. The Homer lidar dataset and ground control referenced above was funded by the Federal Emergency Management Agency (FEMA) through Cooperating Technical Partnership (CTP) with the City of Homer and AK DGGS under federal grant number CTP EMS-2018-CA-00016-S01. We thank Clearwater Air for their aviation expertise and contribution to these data products.
For evaluations of the Grewingk Glacier 1967 landslide scar located above the proglacial lake on the north-facing flank of the glacial valley in Kachemak Bay State Park, Alaska, DGGS capitalized on a data collect (Salisbury and others, 2021) conducted in Homer the same day.
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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: | classified point cloud data, digital surface model, digital terrain model, hydro-flattened digital terrain model, and lidar intensity image in format report point-cloud GeoTIFF |
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https://doi.org/10.14509/30599 |