Abstract

At the Federal Office of Topography, the nationwide digital height model DHM25 was extracted from the Swiss National Map 1: 25, 000 (NM25) between 1984 and 1996. The height information of the NM25 was first converted into the DHM25 basis model. In the rocky area of high Alpine regions, special requirements were necessary: The “Swiss manner” of cliff representation, which is a combination of rock engraving, contour lines with 100m intervals and spot heights, was too weak to represent the height of the break lines correctly. For this reason, additional photogrammetric 3D measurements are necessary, which are made during the normal capture of the revision elements for the NM25. After the capture and the adjustment, these additional elements are integrated into the basis model and will be used for future interpolation of the matrix model.