2018 USGS Lidar DEM: Post Hurricane Maria - USVI eng Dataset EARTH SCIENCE > LAND SURFACE > TOPOGRAPHY > TERRAIN ELEVATION EARTH SCIENCE > OCEANS > BATHYMETRY/SEAFLOOR TOPOGRAPHY > BATHYMETRY > COASTAL BATHYMETRY EARTH SCIENCE > OCEANS > COASTAL PROCESSES > COASTAL ELEVATION elevation CONTINENT > NORTH AMERICA > UNITED STATES OF AMERICA VERTICAL LOCATION > LAND SURFACE VERTICAL LOCATION > SEA FLOOR LIDAR > Light Detection and Ranging Airplane > Airplane U.S. Coastline US Virgin Islands Product: These are Digital Elevation Model (DEM) data for U.S. Virgin Islands as part of the required deliverables for the PR USVI 2018 Lidar project. Class 2 (ground) lidar points in conjunction with the hydro breaklines were used to create a 0.5 meter hydro-flattened Raster DEM. Geographic Extent: St. Croix, US Virgin Islands, covering approximately 82 square miles, St. Thomas and St. John, US Virgin Islands, covering approximately 52 square miles. Dataset Description: PR USVI Lidar project called for the Planning, Acquisition, processing and derivative products of lidar data to be collected at a nominal pulse spacing (NPS) of 0.35 meter. Project specifications are based on the U.S. Geological Survey National Geospatial Program Base Lidar Specification, Version 1.3. The data was developed based on a horizontal projection/datum of NAD83 (2011), Puerto Rico and Virgin Islands, meters and vertical datum of VIVD09 (GEOID12B), meters. Lidar data was delivered as processed Classified LAS 1.4 files, formatted to 301 individual 1500 m x 1500 m tiles, as tiled Intensity Imagery, and as tiled bare earth DEMs; all tiled to the same 1500 m x 1500 m schema. Ground Conditions: Lidar was collected in late 2018, while no snow was on the ground and rivers were at or below normal levels. In order to post process the lidar data to meet task order specifications and meet ASPRS vertical accuracy guidelines, Leading Edge Geomatics established a total of 8 ground control points that were used to calibrate the lidar to known ground locations established throughout the St. Thomas and St. John, US Virgin Islands project area. An additional 32 independent accuracy checkpoints, 26 in Bare Earth and Urban landcovers (26 NVA points), 6 in Tall Grass and Brushland/Low Trees categories (6 VVA points), were used to assess the vertical accuracy of the data. These checkpoints were not used to calibrate or post process the data. NOAA OCM retrieved the DEM files from the USGS rockyftp website below, the files were in GeoTIFF format. ftp://rockyftp.cr.usgs.gov/vdelivery/Datasets/Staged/Elevation/OPR/Projects/PR_PRVI_VI_B1_2018/ ftp://rockyftp.cr.usgs.gov/vdelivery/Datasets/Staged/Elevation/OPR/Projects/PR_PRVI_VI_B2_2018/ OCM Partners OCM Partners https://www.fisheries.noaa.gov/inport/item/60106 https://www.fisheries.noaa.gov/inport/item/49404 northlimit=18.417612; eastlimit=-64.557106; southlimit=17.670113; westlimit=-65.091258; start=2018-05-13; end=2018-06-08; None 2018-12-14