79622 ak2024_merbok_dem_m14098 Data Set Published / External 49404 DEMs - partner (no harvest) Project Completed 2024 2026 Product: Hydro-flattened Digital Elevation Model (DEM) data covering the Typhoon Merbok Alaska Topographic Lidar 2024 project area. Geographic Extent: This dataset and derived products encompass an area covering approximately 894,095 acres on the western coast of Alaska along Norton Sound. AK_TyphoonMerbokNV5_1 - covers approximately 685,389 acres on the western coast of Alaska along Norton Sound AK_TyphoonMerbokNV5_2 - covers approximately 208,706 acres on the western coast of Alaska along Norton Sound Dataset Description: Lidar flight line swaths were processed to create classified LAS 1.4 files delineated in 750 m x 750 m tiles. Each LAS file contains lidar point information, which has been calibrated, controlled, and classified. Class 2 (ground) lidar points in conjunction with the hydro breaklines were used to create 0.5 meter hydro-flattened Raster DEMs delineated in 750 m x 750 m tiles. Additional products include classified LAS files, intensity images, maximum surface height rasters, swath separation RGB images, and 3D breaklines of water bodies within the study area. Ground Conditions: Ground condition was free of snow and acquisition occurred free of smoke, fog and cloud cover. This metadata record supports the data entry in the NOAA Digital Coast Data Access Viewer (DAV). For this data set, the DAV is leveraging the GeoTIFF files hosted by USGS on Amazon Web Services. The purpose of the lidar data was to produce a high accuracy 3D dataset that meets all necessary standards laid out by the 3D Elevation Program and the Typhoon Merbok Alaska Topographic Lidar 2024 contract. The lidar point cloud data were used to create classified lidar LAS files, intensity images, hydro-flattened DEMs, maximum surface height rasters, swath separation RGB images, and 3D breaklines of water bodies within the study area. Raster File Type = TIFF Bit Depth/Pixel Type = 32-bit float Raster Cell Size = 0.5 meter Interpolation or Resampling Technique = Triangulated Irregular Network Required Vertical Accuracy = 19.6 cm NVA Theme Global Change Master Directory (GCMD) Science Keywords EARTH SCIENCE > LAND SURFACE > TOPOGRAPHY > TERRAIN ELEVATION > DIGITAL ELEVATION/TERRAIN MODEL (DEM) Theme Global Change Master Directory (GCMD) Science Keywords EARTH SCIENCE > OCEANS > COASTAL PROCESSES > COASTAL ELEVATION Theme ISO 19115 Topic Category elevation Spatial Global Change Master Directory (GCMD) Location Keywords CONTINENT > NORTH AMERICA > UNITED STATES OF AMERICA Spatial Global Change Master Directory (GCMD) Location Keywords CONTINENT > NORTH AMERICA > UNITED STATES OF AMERICA > ALASKA Spatial Global Change Master Directory (GCMD) Location Keywords VERTICAL LOCATION > LAND SURFACE Instrument Global Change Master Directory (GCMD) Instrument Keywords LIDAR > Light Detection and Ranging Platform Global Change Master Directory (GCMD) Platform Keywords Airplane > Airplane Office for Coastal Management Charleston SC Data Set Elevation None Planned Model (digital) Any conclusions drawn from the analysis of this information are not the responsibility of NOAA, the Office for Coastal Management or its partners. USGS, NV5 Data Steward 2026 Organization NOAA Office for Coastal Management NOAA/OCM coastal.info@noaa.gov 2234 South Hobson Ave Charleston SC 29405-2413 (843) 740-1202 https://coast.noaa.gov NOAA Office for Coastal Management Home Page Online Resource Distributor 2026 Organization NOAA Office for Coastal Management NOAA/OCM coastal.info@noaa.gov 2234 South Hobson Ave Charleston SC 29405-2413 (843) 740-1202 https://coast.noaa.gov NOAA Office for Coastal Management Home Page Online Resource Distributor 2026 Organization U.S. Geological Survey 12201 Sunrise Valley Drive Reston VA 20191 USA https://usgs.gov USGS Home Home page for USGS Online Resource Metadata Contact 2026 Organization NOAA Office for Coastal Management NOAA/OCM coastal.info@noaa.gov 2234 South Hobson Ave Charleston SC 29405-2413 (843) 740-1202 https://coast.noaa.gov NOAA Office for Coastal Management Home Page Online Resource Point of Contact 2026 Organization NOAA Office for Coastal Management NOAA/OCM coastal.info@noaa.gov 2234 South Hobson Ave Charleston SC 29405-2413 (843) 740-1202 https://coast.noaa.gov NOAA Office for Coastal Management Home Page Online Resource Ground Condition AK_TyphoonMerbok_NV5_1 (Work Unit 300810) -164.813766 -161.051935 63.660793 62.740726 Collection area for AK_TyphoonMerbokNV5_1 (Work Unit 300810) Range 2024-06-29 2024-10-14 Dates of collection for AK_TyphoonMerbokNV5_1 (Work Unit 300810) AK_TyphoonMerbok_NV5_2 (Work Unit 301214) -165.115567 -164.363438 63.221599 62.473578 Collection area for AK_TyphoonMerbokNV5_2 (Work Unit 301214) Range 2024-06-29 2025-07-08 Dates of collection for AK_TyphoonMerbokNV5_2 (Work Unit 301214) .5 Meter Yes No No No No Projected EPSG:6332 NAD83(2011) / UTM zone 3N NAD83 (National Spatial Reference System 2011) GRS 1980 6378137 298.257222101 NAD83(2011) UTM zone 3N Transverse Mercator 1 Easting E metre east Vertical EPSG:5703 NAVD88 height North American Vertical Datum 1988 1 Gravity-related height H metre up Custom Universal (CC0 1.0) Public Domain Dedication https://creativecommons.org/publicdomain/zero/1.0/ To the extent possible under law, the U.S. Government has waived all copyright and related or neighboring rights to this dataset. Unclassified Data is available online for bulk and custom downloads. None Users should be aware that temporal changes may have occurred since this data set was collected and some parts of this data may no longer represent actual surface conditions. Users should not use this data for critical applications without a full awareness of its limitations. https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=14098/details/14098 2026 Organization NOAA Office for Coastal Management Customized Download Create custom data files by choosing data area, map projection, file format, etc. A new metadata will be produced to reflect your request using this record as a base. Not Applicable Zip https://prd-tnm.s3.amazonaws.com/index.html?prefix=StagedProducts/Elevation/OPR/Projects/AK_TyphoonMerbok_NV5_F23/ 2026 Organization U.S. Geological Survey Bulk Download Bulk download of data files in the original coordinate system. GeoTIFF https://coast.noaa.gov/dataviewer/ NOAA's Office for Coastal Management (OCM) Data Access Viewer (DAV) Online Resource HTML The Data Access Viewer (DAV) allows a user to search for and download elevation, imagery, and land cover data for the coastal U.S. and its territories. The data, hosted by the NOAA Office for Coastal Management, can be customized and requested for free download through a checkout interface. An email provides a link to the customized data, while the original data set is available through a link within the viewer. https://prd-tnm.s3.amazonaws.com/StagedProducts/Elevation/metadata/AK_TyphoonMerbok_NV5_F23/AK_TyphoonMerbokNV5_1_F23/reports/Merbok_AK_WU1_NOAA_USGS_NIR_lidar_Report_REVISION_081925_Signed.pdf Lidar Report - AK_TyphoonMerbokNV5_1 Online Resource pdf Link to the NV5 lidar report for AK_TyphoonMerbokNV5_1 https://prd-tnm.s3.amazonaws.com/StagedProducts/Elevation/metadata/AK_TyphoonMerbok_NV5_F23/AK_TyphoonMerbokNV5_2_F23/reports/Merbok_AK_WU2_NOAA_USGS_NIR_Lidar_Report.pdf Lidar Report - AK_TyphoonMerbokNV5_2 Online Resource pdf Link to the NV5 lidar report for AK_TyphoonMerbokNV5_2 https://prd-tnm.s3.amazonaws.com/index.html?prefix=StagedProducts/Elevation/metadata/AK_TyphoonMerbok_NV5_F23/ Additional Info Online Resource Link to the additional information available for this data set from the USGS. This information includes reports, tile index shapefiles, and hydro breaklines. https://rockyweb.usgs.gov/vdelivery/Datasets/Staged/Elevation/metadata/AK_TyphoonMerbok_NV5_F23/USGS_AK_TyphoonMerbok_NV5_F23_Project_Report.pdf USGS Project Report Online Resource pdf This USGS report provides the project information, vertical accuracy results, list of classifications, sensor used, and work unit information. Lidar horizontal accuracy is a function of Global Navigation Satellite System (GNSS) derived positional error, flying altitude, and INS derived attitude error. The obtained RMSEr value is multiplied by a conversion factor of 1.7308 to yield the horizontal component of the National Standards for Spatial Data Accuracy (NSSDA) reporting standard where a theoretical point will fall within the obtained radius 95 percent of the time. AK_TyphoonMerbokNV5_1 (Work Unit 300810) Based on a flying altitude of 2016 meters, an IMU error of 0.003 decimal degrees, and a GNSS positional error of 0.023 meters, this project was produced to meet 0.329 meters horizontal accuracy at the 95% confidence level. AK_TyphoonMerbokNV5_2 (Work Unit 301214) Based on a flying altitude of 2016 meters, an IMU error of 0.002 decimal degrees, and a GNSS positional error of 0.023 meters, this project was produced to meet 0.222 meters horizontal accuracy at the 95% confidence level. This data set was produced to meet ASPRS Positional Accuracy Standard for Digital Geospatial Data (2014) for a 10-cm RMSEz Vertical Accuracy Class. USGS Determined DEM Vertical Accuracy Non-Vegetated Vertical Accuracy (NVA) = 2.63 cm RMSE Vegetated Vertical Accuracy (VVA) = 18.97 cm at the 95th Percentile Refer to the USGS Project Report. A link to this report is provided in the URL section of this metadata record. A visual qualitative assessment was performed to ensure data completeness. No void areas or missing data exist. The classified point cloud is of good quality and data passes Non-Vegetated Vertical Accuracy specifications. DEM files were tested by NV5 for vertical accuracy. All data is seamless from one tile to the next, no gaps or no data areas. The NOAA Office for Coastal Management (OCM) ingested references to the USGS GeoTIFF files that are hosted on Amazon Web Services (AWS), into the Digital Coast Data Access Viewer (DAV). The DAV accesses the raster data as it resides on AWS. USGS AWS GeoTIFF Files - AK_TyphoonMerbokNV5_1 Organization USGS Publisher https://prd-tnm.s3.amazonaws.com/index.html?prefix=StagedProducts/Elevation/OPR/Projects/AK_TyphoonMerbok_NV5_F23/AK_TyphoonMerbokNV5_1_F23/TIFF/ USGS AWS GeoTIFF files for AK_TyphoonMerbokNV5_1 USGS AWS GeoTIFF Files - AK_TyphoonMerbokNV5_2 Organization USGS Publisher https://prd-tnm.s3.amazonaws.com/index.html?prefix=StagedProducts/Elevation/OPR/Projects/AK_TyphoonMerbok_NV5_F23/AK_TyphoonMerbokNV5_2_F23/TIFF/ USGS AWS GeoTIFF files for AK_TyphoonMerbokNV5_2 1 Lidar Pre-Processing: 1. Review flight lines and data to ensure complete coverage of the study area and positional accuracy of the laser points. 2. Resolve kinematic corrections for aircraft position data using kinematic aircraft GPS and static ground GPS data. 3. Develop a smoothed best estimate of trajectory (SBET) file that blends post-processed aircraft position with sensor head position and attitude recorded throughout the survey. 4. Calculate laser point position by associating SBET position to each laser point return time, scan angle, intensity, etc. Create raw laser point cloud data for the entire survey in *.las format. Convert data to orthometric elevations by applying a GEOID 12B correction. 5. Import raw laser points into manageable blocks to perform manual relative accuracy calibration and filter erroneous points. Classify ground points for individual flight lines. 6. Using ground classified points per each flight line, test the relative accuracy. Perform automated line-to-line calibrations for system attitude parameters (pitch, roll, heading), mirror flex (scale) and GPS/IMU drift. Calculate calibrations on ground classified points from paired flight lines and apply results to all points in a flight line. Use every flight line for relative accuracy calibration. 7. Adjust the point cloud by comparing ground classified points to supplemental ground control points. 2025-03-26T00:00:00 2 Lidar Post-Processing: 1. Classify data to ground and other client designated classifications using proprietary classification algorithms. 2. Manually QC data classification 3. After completion of classification and final QC approval, calculate final NVA, VVA, and density information for the project using ground control quality check points. 2025-03-26T00:00:00 3 Hydro-flattening Breaklines and Hydro-flattened DEM creation: Water boundary polygons were developed using an algorithm which weights lidar-derived slopes, intensities, and return densities to detect the water's edge. The water's edge was then manually reviewed and edited as necessary. Elevations were assigned to the water’s edge through neighborhood statistics identifying the lowest lidar return from the water surface. Lakes were assigned a consistent elevation for an entire polygon while rivers were assigned consistent elevations on opposing banks and smoothed to ensure downstream flow through the entire river channel. These breaklines were incorporated into the hydro-flattened DEM by enforcing triangle edges (adjacent to the breakline) to the elevation values derived from the breakline. This implementation corrected interpolation along the hard edge. Breaklines were also used to classify all ground points within the identified water bodies to class 9 (water). 2025-03-26T00:00:00 5 The NOAA Office for Coastal Management (OCM) created references to the USGS GeoTIFF files that were ingested into the NOAA Digital Coast Data Access Viewer (DAV). No changes were made to the data. The DAV will access the raster data as it resides on Amazon Web Services (AWS). These are the GeoTIFF files that are being accessed: https://prd-tnm.s3.amazonaws.com/index.html?prefix=StagedProducts/Elevation/OPR/Projects/AK_TyphoonMerbok_NV5_F23/AK_TyphoonMerbokNV5_1_F23/TIFF/ https://prd-tnm.s3.amazonaws.com/index.html?prefix=StagedProducts/Elevation/OPR/Projects/AK_TyphoonMerbok_NV5_F23/AK_TyphoonMerbokNV5_2_F23/TIFF/ 2026-04-22T00:00:00 Organization NOAA Office for Coastal Management NOAA/OCM coastal.info@noaa.gov 2234 South Hobson Ave Charleston SC 29405-2413 (843) 740-1202 https://coast.noaa.gov NOAA Office for Coastal Management Home Page Online Resource 79868 Data Set Cross Reference gov.noaa.nmfs.inport:79622 Rebecca Mataosky 2026-04-22T14:04:19 Rebecca Mataosky 2026-04-30T14:12:05 2026-04-22 OCM Partners OCMP 1002 Public No No 2026-04-22 1 Year 2027-04-22