e9a4049d-886b-43a0-94e4-7e9656b35e1d_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 2021-01-27 ISO 19115 Geographic Information - Metadata ISO 19115:2003/Cor.1:2006(E) Lidar-derived elevation models for Homer, Alaska 2021-01-01 publication Alaska Division of Geological & Geophysical Surveys Fairbanks Alaska, United States publisher Salisbury, J.B. originator Daanen, R.P. originator Herbst, A.M. originator https://doi.org/10.14509/30591 REPORT, POINT CLOUD, GEOTIFF Raw Data File RDF 2021-2 6 p. The Alaska Division of Geological & Geophysical Surveys (DGGS) used lidar to produce digital terrain models (DTM), a digital surface model (DSM), and an intensity model for Homer, Alaska. Detailed bare earth elevation data for Homer were collected and processed for use in a landslide hazard resiliency project for the City of Homer. Data coverage includes neighboring Kachemak City. Lidar and Global Navigation Satellite System (GNSS) data were collected on June 3, 2019, and subsequently processed using TerraSolid and ArcGIS. The Alaska Division of Mining Land & Water (DMLW) Survey Section conducted a targeted Ground Control Survey for this project on June 19-20, 2019. These data are being 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/10.14509/30591). Detailed bare earth elevation data for Homer were collected and processed for use in a landslide hazard resiliency project for the City of Homer. Data coverage includes neighboring Kachemak City. This data release is one of a series of DGGS publications to present elevation data. These data were collected and processed by the Alaska Division of Geological & Geophysical Surveys staff with funding 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. 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) Digital Terrain Model Emergency Preparedness Engineering Engineering Geology Geologic Geology Geomorphology Geotechnical Hazards Landslide Landslide Susceptibility LiDAR Point Cloud Data Remote Sensing Surficial Surficial Geology Topography Web Service theme Alaska Division of Geological & Geophysical Surveys Bear Canyon Beluga Lake Bidarki Creek Bluff Point Bridge Creek Carrie Creek City of Homer City of Kachemak Coal Point Cook Inlet Crossman Ridge Diamond Creek Diamond Gulch Diamond Ridge Homer Homer Spit Kachemak Bay Kachemak City Lampert Lake Mud Bay Neilson Canyon Palmer Creek Twitter Creek Waterman Canyon Woodard Canyon 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). Bluff Point landslide, a massive ancient rock failure near Homer, Alaska 1978-01-01 publication Alaska Division of Geological & Geophysical Surveys Fairbanks Alaska, United States publisher Reger, R.D. originator https://doi.org/10.14509/409 Geologic Report GR 61B p. 5-9 crossReference Landslides in Alaska 2018-01-01 publication Alaska Division of Geological & Geophysical Surveys Fairbanks Alaska, United States publisher Stevens, D.S.P. originator Wolken, G.J. originator Hubbard, T.D. originator Hendricks, K.A. originator https://doi.org/10.14509/29849 Information Circular IC 65 2 p crossReference The Engineering Geology section at DGGS 2019-01-01 publication Alaska Division of Geological & Geophysical Surveys Fairbanks Alaska, United States publisher Stevens, D.S.P. originator https://doi.org/10.14509/30122 Information Circular IC 76 2 p crossReference Updated tsunami inundation maps for Homer and Seldovia, Alaska 2019-01-01 publication Alaska Division of Geological & Geophysical Surveys Fairbanks Alaska, United States publisher Suleimani, E.N. originator Nicolsky, D.J. originator Salisbury, J.B. originator https://doi.org/10.14509/30095 Report of Investigation RI 2018-5 v. 2 97 p., 11 sheets crossReference grid eng; USA geoscientificInformation -151.732364 -151.373102 59.598820 59.709396 2020-06-03 >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. Elevation surfaces interpolated from areas with a point density of fewer than 4 pts/m2 were classified as no data. >digital surface model: DSMs represent surface elevations as they appear to the naked eye. They include 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: DTMs represent 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. >hydro-enforced digital terrain model: The hydro-flattened DTM represents bare earth surfaces which 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 (32-bit, floating-point minimum). 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/10.14509/30591 report point-cloud GeoTIFF classified point cloud data, digital surface model, digital terrain model, hydro-enforced 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 non-vegetated vertical accuracy for classified ground point data is a root mean square error of 3.1 cm. The average pulse spacing is 18.56 cm and the average point density is 29 points per square meter. See accompanying report for more detail. This dataset is a partial release of the June 3, 2019 lidar project. After the refuel stop, the survey moved across Kachemak Bay to scan the north-facing flank of the Grewingk Glacier valley (the site of a 1967 landslide into the proglacial lake). Data covering the Grewingk Glacier landslide scar will be published separately. However, data quality portrayed here for Homer and Kachemak is consistent throughout the entire dataset. This dataset is a partial release of the June 3, 2019 lidar project. After the refuel stop, the survey moved across Kachemak Bay to scan the north-facing flank of the Grewingk Glacier valley (the site of a 1967 landslide into the proglacial lake). Data covering the Grewingk Glacier landslide scar will be published separately. However, data quality portrayed here for Homer and Kachemak is consistent throughout the entire dataset. The relative accuracy for this dataset is 10.38 cm RMSE, calculated as the interswath consistency. Heavy air traffic precluded sufficient scanning of the southwestern portion of Beluga Lake and an area southeast of the Homer Airport runway (along Kachemak Drive). The low-quality data at the southwest end of Beluga Lake has been clipped and flattened to lake level. The tests and processing methods used to ensure data consistency are further described in the accompanying report. This lineage was generated by the FGDC CSDGM to 19139 transformation Airborne survey - DGGS operates a Riegl VUX1-LR laser scanner with a GNSS and Northrop Grumman Inertial Measurement Unit (IMU). The integration was designed by Phoenix LiDAR systems. The sensor can collect up to 820,000 points per second over a 150 m range. We flew the instrument with a repetition rate of 400,000 pulses per second, a scan speed of 200 revolutions per second, at approximately 200 m above ground level, and at a ground speed of approximately 40 meters per second with a fixed-wing Cessna 185. The scan look angle operated between 55 and 305 degrees. The total data coverage is approximately 98 km2. DGGS collected lidar data on June 3, 2019, initiating the GNSS base station at 08h48 and flying from 10h15 to 15h35 with a 15-minute refuel at 14h15. The sky was clear with light, easterly winds. Heavy air traffic precluded sufficient scanning of the southwestern portion of Beluga Lake and an area southeast of the Homer Airport runway (along Kachemak Drive). 2020-06-03T00:00:00 Ground survey - The Alaska Division of Mining, Land, & Water Survey Section collected 79 points in a targeted Ground Control Survey in Homer on June 19-20, 2019. 2020-06-20T00:00:00 Lidar dataset processing - DGGS processed raw data by first using SDCImport to apply range thresholding, reflectance thresholding, and missed-time-around (MTA) disambiguation for preliminary point cloud noise filtering. We coupled in-flight IMU and GNSS data in Inertial Explorer to produce flight trajectory data and coupled the trajectory data with the raw point cloud in Spatial Explorer. We then used Terrasolid to calibrate point cloud data using tielines for roll, pitch, and yaw of the aircraft during the survey. We completed this process first for all points, then on a per-flight-line basis. For additional calibration, we identified interswath fluctuations in preliminarily-classified ground points using overlapping tielines. We classified the point cloud in accordance with American Society for Photogrammetry and Remote Sensing (ASPRS) guidelines using project-tailored macros, resulting in a ground points class, 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). Misclassified points were manually reclassified in post-processing QA/QC. We eliminated all low points and air points from the dataset and manually identified some buildings under dense vegetation, particularly in areas of complex terrain. We hydro-flattened the Bridge Creek Reservoir, Beluga Lake, and Lampert Lake to specified elevations. Lastly, we converted the point cloud from ellipsoidal to orthometric heights using GEOID 12B, then uniformly adjusted the dataset to maintain a mean offset of 0 m with collected ground control. All derivative products were created in ArcMap. The DTM and DSM were produced using point triangulation with nearest-neighbor interpolation. The DTM was derived from all returns for ground classified points, while the DSM used first returns for all non-noise classes. A lidar intensity image was created from first returns of all classes using mean binning. 2020-01-01T00:00:00 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