Abstract:
Digital elevation models (DEMs) are an important basis for many archaeological GIS studies like predictive modelling, visibility and least-cost path analysis. Issues in DEM data have been discussed in textbooks dealing with archaeological GIS applications and in some papers published more than ten years ago. But lately hardly any archaeological GIS study relying on DEM data refer to these issues though the problems connected with DEM use have not decreased with increasing availability of DEM data. This contribution presents a case study in the East Andean slopes of Ecuador analysing the impact of DEM choice on slope and aspect calculation as well as least-cost site catchments and least-cost paths. Four freely available elevation data sets are considered: ASTER GDEM2, SRTM at 3 arc-second and 1 arc-second resolution as well as a DEM derived from digitised contour lines of the official 1:50,000 maps provided by the Military Geographical Institute of Ecuador. Issues discussed are DEM resolution, horizontal and vertical
accuracy, filling voids, and creating a DEM from contour lines.