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description:
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Product: These are Digital Elevation Model (DEM) data for the Umbagog NH/ME 2016 LiDAR project. Class 2 (ground) lidar points in conjunction with the hydro breaklines were used to create a 1-meter hydro-flattened raster DEM. Geographic Extent: Partial coverage of six counties in New Hampshire and Maine, covering approximately 3,276 total square miles. Dataset Description: The Umbagog NH/ME 2016 LiDAR project called for the planning, acquisition, processing, and derivative products of LiDAR data to be collected at a nominal pulse spacing (NPS) of 0.7 meters for the New Hampshire, Maine, and FEMA R1 (MOD1) areas of interest. The White Mountain National Forest NH/ME areas of interest used LiDAR collected at 0.57 meters NPS, with the MOD2 WMNF addon collected at 0.35 NPS. Project specifications are based on the U.S. Geological Survey National Geospatial Program Base LiDAR Specification, Version 1.2. The data for counties in the AOI were developed based on a horizontal projection/datum of NAD83 (2011), UTM Zone 19, meters and vertical datum of NAVD88 (GEOID12B), meters. LiDAR data were delivered as flightline-extent unclassified LAS swaths, as processed Classified LAS 1.4 files formatted to 3,465 individual 1,500-meter x 1,500-meter tiles, along with 283 individual 750-meter x 750-meter tiles for the MOD2 WMNF addon area of interest, as tiled 1-meter intensity imagery in GeoTIFF format, and as tiled 1-meter hydro-flattened bare earth DEMs in GeoTIFF format; all tiled to the same schema. Continuous breaklines were produced in Esri file geodatabase format. Ground Conditions: LiDAR was collected from spring of 2016 to spring of 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, Quantum Spatial, Inc. utilized a total of 68 ground control points that were used to calibrate the LiDAR to known ground locations established throughout the project area. An additional 165 independent accuracy checkpoints, 95 in Bare Earth and Urban landcovers (95 NVA points), 70 in Tall Weeds categories (70 VVA points), were used to assess the vertical accuracy of the data. These checkpoints were not used to calibrate or post process the data. |
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tags:
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["elevation","elev","LiDAR","LiDAR derivative","surface","Digital Elevation Model","DEM","Maine","USGS","Umbagog 2016","2016"] |