ASIS2015_HRJQ_BE_z18_n88g12B_mosaic_metadata: Lidar-Derived Bare-Earth Digital Elevation Model (DEM) Mosaic for Coastal Topography—Assateague Island, Maryland and Virginia, Post-Hurricane Joaquin, 26 November 2015

Quantum Spatial reports that the contract specifications required that only Nonvegetated Vertical Accuracy (NVA) were computed for raw lidar point cloud swath files. The vertical accuracy was tested with 13 independent surveys located in open terrain. These check points were not used in the calibration or post-processing of the lidar point cloud data. The survey check points were distributed throughout the project area. The independent check points were surveyed using the closed level loop technique. Elevations from the unclassified lidar surface were measured for the x,y location of each check point. Elevations interpolated from the lidar surface were then compared to the elevation values of the surveyed control. The RMSE was computed to be 0.042. AccuracyZ has been tested as 0.082 meters AccuracyZ at 95 percent Confidence Interval, meeting 19.6 cm NVA at 95 percent confidence level using (RMSEz * 1.9600) as defined by the National Standards for Spatial Data Accuracy (NSSDA); assessed and reported using National Digital Elevation Program (NDEP)/American Society of Photogrammetry and Remote Sensing (ASPRS) Guidelines.