Central Mississippi River Work Unit 1; Hydro-Flattened Bare-Earth DEM

Product: 0.5-meter bare-earth raster digital elevation model (DEM) data tiles in GeoTIFF format.<br/>Geographic Extent: Approximately 495 square miles in the southeast Minnesota area.<br/>Dataset Description: MN Central Miss River 1 B22 lidar project called for the planning, acquisition, processing, and production of derivative products of QL1 lidar data to be collected an aggregate nominal pulse spacing (ANPS) of 0.18-meters and 30 points per square meter (ppsm). Project specifications were based on the U.S. Geological Survey National Geospatial Program Base Lidar Specification, Version 2022 revision A. The data was developed based on a horizontal reference system of NAD83 (2011) UTM 15 meters (EPSG 6344) and a vertical reference system of NAVD88 (GEOID18) meters. DEM data was delivered as processed GeoTIFF files formatted to 5,396 individual 500-meters x 500-meters tiles.<br/>Ground Conditions: Lidar was collected from May 14, 2022, through May 27, 2022 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, Woolpert established ground control points that were used to calibrate the lidar to known ground locations established throughout the entire project area. An additional independent accuracy checkpoints were collected throughout the entire project area and used to assess the vertical accuracy of the data. These checkpoints were not used to calibrate or post process the data.