Jeffrey Irwin Travis Kropuenske Aparajithan Sampath 2025 <p>A geometric accuracy assessment of lidar data collected in eastern Iowa in 2019 as part of the 3D Elevation Program (3DEP) was conducted. The assessment involved evaluating interswath accuracy, same surface precision, point density, absolute accuracy, and consistency with adjacent 3DEP datasets. The results demonstrate that the data meet or exceed the quality level 2 specifications outlined in the Lidar Base Specifications (LBS). Interswath and same surface precision values were within specified tolerances, with a root mean square difference of 0.03 meters for interswath vertical accuracy and 0.03 meters for same surface precision. Vertical accuracy in flat areas was excellent, with root mean square error values consistently below 0.10 meters. Horizontal accuracy assessments also showed good agreement between lidar and reference data. Point density generally exceeded the minimum requirement of 2 points per square meter, and the inter-project consistency assessment indicated good agreement between the Iowa lidar data and adjacent datasets.</p> application/pdf 10.3133/ofr20251017 en U.S. Geological Survey Validation of the geometric accuracy of airborne light detection and ranging data for eastern Iowa, 2019 reports