Elevation accuracy assessment of a DSM and DTM generated for an urban area from the ALTM 2025 airborne laser scanning sensor

摘要

The assessment of elevation accuracy of digital elevation models (DEM), which comprise digital surface models (DSM) and digital terrain models (DTM), has become a recurrent theme in the scientific literature in the latest decades. Accuracy tests are specifically based on a 10% level of statistical significance and they comprise both trend and precision analyses. Both tests were applied to data obtained from an air survey accomplished with the ALTM 2025 laser scanning sensor for a central sector of Uberlandia city, Brazil. The statistical tests for the DSM and DTM demonstrated that the mean elevation error respectively lay around 0,41 m and 0,48 m, and the RMSE about 0,48 m and 0,47 m. In both cases, the presence of trend in the H direction was observed, revealing systematic influences in this component. This trend was further removed by means of algebraic manipulations. The precision analysis revealed that the DSM and DTM were compatible with a 1∶5,000 scale and were up to the standard of the highest cartographic accuracy category (class A - PEC).