{"action":"create","ckan_id":null,"date_created":"Sat, 07 Mar 2026 20:46:55 GMT","date_finished":null,"harvest_job_id":"5146f61a-f575-4df8-8eeb-1e0f3906084a","harvest_source_id":"31f41541-38a0-400b-b240-10ebcb0acd9a","id":"f5d6d1d1-f398-48c4-aff0-66673bb6f04b","identifier":"https://dggs.alaska.gov/webpubs/metadata/RDF2024-6.xml","parent_identifier":null,"source_hash":"e88fb5fc8fe48ab5b216fcbdb63c3c49c93c224be5ebbcf960ca0d7df4780bf8","source_raw":"Zechmann, J.M.Wikstrom Jones, K.M.Wolken, G.J.2024Lidar-derived elevation data for Cordova, Southcentral Alaska, collected August 18-19, 2023, and September 19 and 22, 2023dataRaw Data FileRDF 2024-6Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys11 p.https://doi.org/10.14509/31159Lidar-derived elevation data for Cordova, Southcentral Alaska, collected August 18-19, 2023, and September 19 and 22, 2023, Raw Data File 2024-6, classified point cloud, digital surface model (DSM), digital terrain model (DTM), and an intensity model of Cordova, Southcentral Alaska during leaf-on conditions. The survey provides snow-free surface elevations for landslide and avalanche hazard assessments. Ground control data were collected August 16-17, 2023; aerial lidar data were collected August 18-19, 2023, and September 19 and 22, 2023, and subsequently merged and processed using a suite of geospatial processing software. This data collection is released as a Raw Data File with an open end-user license. All files can be downloaded from the Alaska Division of Geological & Geophysical Surveys website (http://doi.org/10.14509/31159).These data provide snow-free surface elevations for deriving snow depth distribution models with repeat surveys during snow-covered conditions.>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.\t\r\n>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 classified ground points, the average point density is 2.84 pts/m2, and the average spacing is 59.3 cm.\t\r\n>dsm_hydro_flattened: The DSM represents surface elevations, including heights of vegetation, buildings, powerlines, bridge decks, etc. It is a single-band, 32-bit GeoTIFF file with a 50-cm resolution. The data value is set to -3.40282306074e+38 (32-bit, floating-point minimum).\t\r\n>dtm_hydro_flattened: The DTM represents bare earth elevations, excluding vegetation, bridge decks, buildings, etc. The DTM is a single-band, 32-bit GeoTIFF file of 50-cm resolution. No Data value is set to -3.40282306074e+38.\t\r\n>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, 32-bit GeoTIFF file of 50-cm resolution. No Data value is set to -3.40282306074e+38.2023081620230922ground conditioncompleteNone planned-145.991631-145.41261060.71700060.437462ISO 19115 Topic CategorygeoscientificInformationAlaska Division of Geological & Geophysical SurveysDGGSDigital Elevation ModelDigital Surface Model (DSM)Digital Terrain ModelElevationEmergency PreparednessEngineeringEngineering GeologyGeologicGeologic HazardsGeological ProcessGeologyGeomorphologyGeotechnicalHazardsLandslideLandslide SusceptibilityLiDARLiDAR Intensity ImageLiDAR LAS File FormatPoint Cloud DataRaster ImageRemote SensingSlopeSlope InstabilitySurfaceSurficialSurficial GeologyTopographyAlaska Division of Geological & Geophysical SurveysBeartrail CreekBoy Scout IslandCity of CordovaCopper River HighwayCordovaCrater LakeCrystal FallsEccles CreekEccles LagoonEyakEyak LakeEyak RiverFleming CreekGulf of AlaskaHartney BayHartney CreekHeney CreekHeney PeakHeney RangeHumpback CreekIbeck CreekKelly MountainMavis IslandMeals LakeMiddle ArmMount EcclesMount EyakMount Robert KornMount ShielsNicolet CreekOdiak LagoonOhman FallsOrcaOrca InletPower CreekScout LakeShag RockSpike IslandThree Mile BayTripod HillWhitshedThis 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 on the traditional homelands of the Eyak people. The Federal Emergency Management Agency (FEMA) grant number EMS-2021-CA-00014 funded this work. We thank Clearwater Air for their aviation expertise and contribution to these data products and the DMLW for providing ground control points and checkpoints. The views and conclusions contained in this document are those of the authors. They should not be interpreted as necessarily representing the official policies, either expressed or implied, of the U.S. Government.Nicolsky, D.J.Suleimani, E.N.Koehler, R.D.2014Tsunami inundation maps of Cordova and Tatitlek, AlaskaReport of InvestigationRI 2014-1Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys49 p., 2 sheets, scale 1:31,000https://doi.org/10.14509/27241Stevens, D.S.P.Campbell, K.M.Reger, R.D.Smith, R.L.2003Survey of geology, geologic materials, and geologic hazards in proposed access corridors in the Cordova Quadrangle, AlaskaMiscellaneous PublicationMP 64Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys5 sheets, scale 1:250,000https://doi.org/10.14509/3263Wolken, 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 applicableThis is a full-release dataset. There was no over-collect. Data quality is consistent throughout the survey, except for high-elevation glaciated areas, where few laser returns resulted in interpolated areas.This data release is complete.We did not measure horizontal accuracy for this collection.We measured a mean offset of -164.1 cm between 25 control points and the point cloud. This offset was reduced to -0.7 cm in non-vegetated areas by applying a constant vertical correction to the lidar point data. In vegetated areas, checkpoints show the average offset to be +16.3 cm. We used 57 non-vegetated and 69 vegetated 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 7.8 cm in non-vegetated areas and 26.6 cm in vegetated areas. We evaluated the relative accuracy for this dataset as the interswath overlap consistency and measured it at 7.7 cm RMSE.Ground survey - The State of Alaska, Division of Mining, Land, and Water (DMLW) collected ground control points on August 16 and 17, 2023. They deployed a Trimble R12 GNSS receiver to provide a base station occupation and real-time kinematic (RTK) corrections to points they surveyed with a rover Trimble R12 GNSS receiver/TSC5 controller. A brass disk with designation 945 4050 H and PID BBGS17, located along Orca Inlet Road 0.5 km south of Cordova Ferry Terminal, served as a base station location. One hundred fifty-one ground control points and checkpoints were collected for calibration and to assess the vertical accuracy of the point cloud. Checkpoints were collected on bare earth and in low vegetation, shrubland, and forest.20230817Aerial 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 1,000 m (ranges assume greater than or equal to 20 percent natural reflectance). The scanner operated with a pulse refresh rate of 200,000 pulses per second over alpine terrain and 400,000-600,000 pulses per second over forested terrain, with a scan rate of 65-195 revolutions per second. We used a Cessna 180 Skywagon fixed-wing platform to survey from an elevation of approximately 230-390 m above ground level at a ground speed of approximately 40 m/s, with a scan angle set from 80 to 280 degrees. The total survey area covers approximately 298 km2. The survey area was accessed by air from Cordova Municipal Airport and Merle K. (Mudhole) Smith Airport. Flightlines are shown in figure 1 of the accompanying report. See table 1 for data collection start and end times and weather conditions.20230923Lidar dataset 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. For the lidar data collection, the average pulse density is 23.0 pulses/m2 and the average pulse spacing is 20.8 cm. 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 50-cm DSM was interpolated from ground, vegetation, bridge deck, and building classes using a binning method and maximum values. A 50-cm DTM was interpolated from all ground class returns using a binning method and minimum values. We also produced a 50-cm intensity image for the entire area using average binning in ArcGIS Pro, with no normalization or corrections applied.2023rasterUniversal Transverse Mercator60.999600-1470500000.0000000coordinate pair.00000001.00000001MetersNAD83 (2011)GRS 806378137298.257222101NAVD88, GEOID12B0.001metersExplicit 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 classified ground points, the average point density is 2.84 pts/m2, and the average spacing is 59.3 cm.DGGSclassified_pointsdsm_hydro_flattenedThe DSM represents surface elevations, including heights of vegetation, buildings, powerlines, bridge decks, etc. It is a single-band, 32-bit GeoTIFF file with a 50-cm resolution. The data value is set to -3.40282306074e+38 (32-bit, floating-point minimum).DGGSdsm_hydro_flatteneddtm_hydro_flattenedThe DTM represents bare earth elevations, excluding vegetation, bridge decks, buildings, etc. The DTM is a single-band, 32-bit GeoTIFF file of 50-cm resolution. No Data value is set to -3.40282306074e+38.DGGSdtm_hydro_flattenedlidar_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, 32-bit GeoTIFF file of 50-cm resolution. No Data value is set to -3.40282306074e+38.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 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.RDF 2024-6The 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.DGGS publications are available as free online downloads or you may purchase paper hard-copies or digital files on CD/DVD or other digital storage media by mail, phone, fax, or email from the DGGS Fairbanks office. To purchase this or other printed reports and maps, contact DGGS by phone (907-451-5020), e-mail (dggspubs@alaska.gov), or fax (907-451-5050). Payment accepted: Cash, check, money order, VISA, or MasterCard. Turnaround time is 1-2 weeks unless special arrangements are made and an express fee is paid. Shipping charge will be the actual cost of postage and will be added to the total amount due. Contact us for the exact shipping amount.Contact DGGS for current pricingdata20240410boundaries, classified points, dsm hydro flattened, dtm hydro flattened and lidar intensityhttps://doi.org/10.14509/31159Free download20240410Alaska Division of Geological & Geophysical SurveysSimone MontayneMetadata 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","source_transform":null,"status":"error"}