A New Method for Checking the Planimetric Accuracy of Digital Elevation Models Data Derived by Airborne Laser Scanning
Abstract: The current state of the art in checking the planimetric accuracy of Digital Elevation Models derived from Airborne Laser Scanning is analyzed. The principle of a proposed method is presented including the mathematical equations. Special emphasis is given to the precision of derived points which are used for the comparison with true values. Least squares adjustment is applied and the influence of blunders in the observations is reduced by means of the iterative determination of weights as a function of the size of the corrections. Practical tests have been carried out with data from the new Digital Elevation Model of Denmark. The required reference values were derived by means of aerial images and photogrammetric techniques. A few ground control points were determined by GPS. The reliability and practicability of the method is then discussed on the basis of the experiences obtained from the practical usage of the method. It is concluded that the proposed method is accurate, robust against blunders and with potential for automation.
Keywords: Digital Elevation Models; Airborne Laser Scanning; planimetric accuracy; robust adjustment; precision