Lidar-derived elevation data for Blackerby parcel, Juneau, southeast Alaska, collected July 12, 2023

Zechmann, J.M.Larsen, M.C.Wikstrom Jones, K.M.2025Lidar-derived elevation data for Blackerby parcel, Juneau, southeast Alaska, collected July 12, 2023dataRaw Data FileRDF 2024-8Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys8 p.https://doi.org/10.14509/31161Lidar-derived elevation data for Blackerby parcel, Juneau, southeast Alaska, collected July 12, 2023, Raw Data File 2024-8 releases classified point cloud derived from aerial lidar, along with a digital surface model (DSM), a digital terrain model (DTM), and an intensity model of slopes above the Blackerby Parcel in Juneau, Southeast Alaska, during leaf-on conditions. The survey provides snow-free surface elevations for use in landslide hazard assessment, geologic mapping, and slope-stability analysis. Ground control data provided by the Alaska Department of Transportation (DOT) was collected on March 21, 2017. DGGS collected aerial lidar data on July 12, 2023, and subsequently merged and processed using a suite of geospatial processing software. This collection is available as a Raw Data File under an open end-user license. All files can be downloaded from the Alaska Division of Geological & Geophysical Surveys website (http://doi.org/10.14509/31161).The data were collected during leaf-on conditions and provides snow-free surface elevations useful for landslide hazard analysis.>boundaries: A boundary, also known as an Area of Interest (AOI) or border, that defines the area covered by the data. Also includes footprints for tiled data. >classified_points: Classified point cloud data are provided in LAZ format. Data are classified following ASPRS 2019 guidelines and contain return and intensity information. For all ground points, the average point spacing is 48.4 cm, and the average density is 4.27 pts/m2 >dsm: The DSM represents surface elevations, including heights of vegetation, buildings, powerlines, bridge decks, etc. It is a single-band, 32-bit GeoTIFF file of 20-cm resolution. No Data value is set to -3.40282306074e+38 (32-bit, floating-point minimum). >dtm: The DTM represents bare earth elevations, excluding vegetation, bridge decks, buildings, etc. The DTM is a single-band, 32-bit GeoTIFF file of 20-cm resolution. 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 (1) primarily a function of scanned object reflectance in relation to the signal frequency, (2) dependent on ambient conditions, and (3) not necessarily consistent between separate scans. The intensity image is a single-band, 16-bit unsigned GeoTIFF file of 20-cm resolution. No Data value is set to 0.2017030120230712ground conditioncompleteNone planned-134.500809-134.44870258.36020658.326341ISO 19115 Topic CategorygeoscientificInformationAlaska Division of Geological & Geophysical SurveysAerialAerial GeologyCoastalCoastal and RiverDGGSDigital Elevation ModelDigital Surface Model (DSM)Digital Terrain ModelElevationEmergency PreparednessEngineeringEngineering GeologyEnvironmentalGeologicGeologic HazardsGeological ProcessGeologyGeomorphologyGeotechnicalHazardsLandslideLandslide SusceptibilityLiDARLiDAR Intensity ImageLiDAR LAS File FormatPoint Cloud DataRaster ImageRemote SensingSlopeSlope InstabilitySurfaceSurficialSurficial GeologyTopographyUnconsolidated DepositsAlaska Division of Geological & Geophysical SurveysGastineau ChannelJuneauLemon CreekSalmon CreekSoutheast AlaskaVanderbilt HillWalker, J.D., Geissman, J.W., Bowring, S.A, and Babcock, L.E., comp., 2012, Geologic Time Scale v. 4.0: Geological Society of AmericaHoloceneThis 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).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.Alaska Division of Geological & Geophysical SurveysMetadata Managermailing and physical

3354 College Road

FairbanksAK99709-3707USA(907)451-5020(907)451-5050dggspubs@alaska.gov8 am to 4:30 pm, Monday through Friday, except State holidaysPlease 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.This survey area is located within the traditional homelands of the A'akw Kwaan and T'aaá¸µu á¸´waan Tlingit peoples. This work was funded by the Alaska Division of Mining, Land, and Water (Reimbursable Services Agreement-IPO 230001027). We thank Clearwater Air for their aviation expertise and contribution to these data products and the Alaska Department of Transportation for providing ground control points. The views and conclusions contained in this document are those of the authors. They should not be interpreted as necessarily representing the State of Alaska's official policies, either expressed or implied.Nicolsky, D.J.Suleimani, E.N.Koehler, R.D.Salisbury, J.B.2017Tsunami inundation maps for Juneau, AlaskaReport of InvestigationRI 2017-9Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys66 p., 5 sheetshttps://doi.org/10.14509/29741Stevens, D.S.P.Wolken, G.J.Hubbard, T.D.Hendricks, K.A.2018Landslides in AlaskaInformation CircularIC 65Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys2 phttps://doi.org/10.14509/29849Wikstrom Jones, K.M.Wolken, G.J.2022Lidar-derived elevation data for Mount Juneau, Southeast Alaska, collected September 6, 2019Raw Data FileRDF 2021-12Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys8 phttps://doi.org/10.14509/30731Wolken, G.J.Hendricks, K.A.Daanen, R.P.Overbeck, J.R.Stevens, D.S.P.Masterman, S.S.2017Alaska & climate changeInformation CircularIC 64Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys2 phttps://doi.org/10.14509/29781Not applicableDGGS visually inspected the orthoimage for data errors such as shifts, seamline mismatches, and water noise overlapping land. There were no significantly erroneous areas that required repair. Data quality is consistent throughout the survey. There was no over-collect.This is a full-release dataset.Horizontal accuracy was not measured for this collection.We measured a mean offset of +68.3 cm between 23 control points and the point cloud. This offset was reduced to +0.1 cm by applying a static vertical correction to the lidar point data. We used 13 checkpoints to determine the vertical accuracy of the point cloud ground class using a Triangulated Irregular Network (TIN) approach. The project vertical accuracy has a root mean square error (RMSE) of 3.9 cm. We evaluated the relative accuracy for this dataset as the interswath overlap consistency and measured it at 8.4 cm RMSE.Ground survey - The Alaska Department of Transportation collected ground control points along the centerline of Glacier Highway in Juneau on March 21, 2017. They deployed a Leica GS-15 for static GPS control for points they surveyed with a Leica TS15 total station. DOT collected 36 ground control points and checkpoints (all located on paved surfaces), which we use for calibration and to assess the vertical accuracy of the point cloud.20170301Aerial survey - DGGS used a Riegl VUX1-LR22 laser scanner integrated with a global navigation satellite system (GNSS) and Northrop Grumman LN-200C inertial measurement unit (IMU) designed by Phoenix LiDAR Systems. The sensor can collect a maximum of 1,500,000 points per second at a range of 230 m or a minimum of 50,000 points per second at a range of 1000 m (ranges assume approximately 20 percent natural reflectance). The scanner operated with a pulse refresh rate of 600,000 pulses per second, with a scan rate of 200 lines per second. We used a Cessna 180 fixed-wing platform to survey from an elevation of approximately 150 m above ground level, at a ground speed of approximately 40 m/s, and with a scan angle set from 80 to 280 degrees. The total survey area covers approximately 7.4 km2. The survey area was accessed by air from Juneau International Airport. Data collection began at 1:40 p.m. (AST) and ended at 2:00 p.m. (AST). The weather was partly cloudy with no wind.20230712Dataset processing - We processed point data in Spatial Explorer for initial filtering and multiple-time-around (MTA) disambiguation. MTA errors, corrected in this process, result from ambiguous interpretations of received pulse time intervals and occur more frequently with higher pulse refresh rates. IMU and GNSS data were processed in Inertial Explorer, and flightline information was integrated with the point cloud in Spatial Explorer. We calibrated the point data at an incrementally precise scale of sensor movement and behavior, incorporating sensor velocity, roll, pitch, and yaw fluctuations throughout the survey. We created macros in Terrasolid software and classified points in accordance with the American Society for Photogrammetry & Remote Sensing (ASPRS) 2019 guidelines (ASPRS, 2019). Once classified, we applied a geometric transformation and converted the points from ellipsoidal heights to GEOID12B (Alaska) orthometric heights. Raster products were derived from the point cloud in ArcGIS Pro. A 20-cm DSM was interpolated from maximum-return values from ground, vegetation, bridge deck, and building classes using a binning method and maximum values. A 20-cm DTM was interpolated from all ground-class returns using a binning method and minimum values. We also produced a 20-cm intensity image for the entire area using average binning in ArcGIS Pro, with no normalization or corrections applied.2024rasterUniversal Transverse Mercator80.999600-1350500000.0000000coordinate pair.00000001.00000001MetersNAD83 (2011)GRS 806378137298.257222101NAVD88, GEOID12B0.500000metersExplicit elevation coordinate included with horizontal coordinatesboundariesA boundary, also known as an Area of Interest (AOI) or border, that defines the area covered by the data. Also includes footprints for tiled data.DGGSboundariesclassified_pointsClassified point cloud data are provided in LAZ format. Data are classified following ASPRS 2019 guidelines and contain return and intensity information. For all ground points, the average point spacing is 48.4 cm, and the average density is 4.27 pts/m2DGGSclassified_pointsdsmThe DSM represents surface elevations, including heights of vegetation, buildings, powerlines, bridge decks, etc. It is a single-band, 32-bit GeoTIFF file of 20-cm resolution. No Data value is set to -3.40282306074e+38 (32-bit, floating-point minimum).DGGSdsmdtmThe DTM represents bare earth elevations, excluding vegetation, bridge decks, buildings, etc. The DTM is a single-band, 32-bit GeoTIFF file of 20-cm resolution. No Data value is set to -3.40282306074e+38.DGGSdtmlidar_intensityThe lidar intensity image describes the relative amplitude of reflected signals contributing to the point cloud. Lidar intensity is (1) primarily a function of scanned object reflectance in relation to the signal frequency, (2) dependent on ambient conditions, and (3) not necessarily consistent between separate scans. The intensity image is a single-band, 16-bit unsigned GeoTIFF file of 20-cm resolution. No Data value is set to 0.DGGSlidar_intensityAlaska Division of Geological & Geophysical SurveysMetadata Managermailing and physical

3354 College Road

FairbanksAK99709-3707USA(907)451-5020(907)451-5050dggspubs@alaska.gov8 am to 4:30 pm, Monday through Friday, except State holidaysFGDC Content Standard for Digital Geospatial MetadataFGDC-STD-001-1998If 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.https://dggs.alaska.gov/metadata/dggs.extdggs metadata extensions