This thesis involves quality control of digital terrain models (DTM). The initial analysis elucidates the elements which affects the quality of elevation models. The projects main analysis examines the accuracy of both KMS and COWIs DTM. The main analysis is divided into three parts, where the first part is a relative comparison, which involves a raster analysis that describes the differences between the DTMs. The second part concerns a analysis of height accuracy of the two DTMs. The analysis involves 629 surveyed controlpoints in six locations. The first location is used as reference, and the RMS for KMS's DTM in this location is 7 cm, whereas the RMS for COWIs DTM is 6,8 cm. The additional locations are chosen on the basis of the initial analysis, and are areas where an inferior accuracy is expected. An overall RMS of 33,5 cm for KMS´s DTM and 39,5 cm for COWI´s DTM is calculated for all locations. The third part concerns planimetric accuracy of pointclouds collected by airborne laser scanning. This analysis compares eight controlpoints, which can be defined in the two pointclouds and surveyed. The overall planimetric accuracy is 59 cm for KMS´s pointcloud and 60 cm for COWI´s pointcloud.