Rainy Lake Work Unit 1-4; Hydro-Flattened Bare-Earth DEM

Product: These are Digital Elevation Model (DEM) data for Minnesota as part of the required deliverables for the MN_RainyLake_2020_B20_MN3DGEO project. Class 2 (ground) LiDAR points in conjunction with the hydro breaklines were used to create a 0.5 meter hydro-flattened Raster DEM.<br/>Geographic Extent: 8 counties in Minnesota, covering approximately 11989 total square miles.<br/>Dataset Description: The MN_RainyLake_2020_B20_MN3DGEO 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 meters. Project specifications are based on the U.S. Geological Survey National Geospatial Program Base LiDAR Specification, Version 2.1. The data were developed based on a horizontal projection/datum of NAD 1983 2011 UTM Zone 15N, Meter and vertical datum of NAVD88 Geoid 18, Meter. LiDAR data were delivered as processed Classified LAS 1.4 files formatted to 31053 individual 1000m x 1000m tiles, as tiled intensity imagery, and as tiled bare earth DEMs; all tiled to the same 1000m x 1000m schema. Continuous breaklines were produced in Esri file geodatabase format. A total of 42 tiles are located over water and contains no deliverable points. Because of this, there are 42 fewer LAS and intensity deliverables than the 31,053 that appear in the tile index.<br/>Ground Conditions: LiDAR was collected in spring 2021, 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, NV5 Geospatial utilized a total of 228 ground control points that were used to calibrate the LiDAR to known ground locations established throughout the project area. An additional 386 independent accuracy checkpoints, 226 in Bare Earth and Urban landcovers (226 NVA points), 160 in Tall Weeds categories (160 VVA points), were used to assess the vertical accuracy of the data. These checkpoints were not used to calibrate or post process the data.