Final Activity Report Summary - CLUE (Complex Landscape Units for Environmental assessment and modelling) The CLUE project bridged methods of Geographic information system (GIS), GIS and image processing with more traditional disciplines of physical geography and geomorphology. The overall aim was to develop a method to automatically derive landform elements from Digital terrain models (DTM) or Digital elevation models (DEM), respectively. DEMs are widely accessible today. Following the worldwide coverage from the Shuttle radar topography mission (SRTM) mission, i.e. the space shuttle flown radar based elevation model, most industrialised countries and emerging economies have high resolution data sets available, which represent a smaller than 50 m grid resolution. These raster data sets are widely used in, for example, visual illustrations or terrain analysis. Within the CLUE project a methodology of classifying landform elements was established. Results were published in journals and book chapters and presented at conferences. New methods for validating classification outputs of terrain data were developed. Through these achievements it was possible to derive semi-automatically (some corrections of the underlying rule sets were necessary only when applying the methodology to very flat areas or specific high mountain landscapes) landform elements such as 'peaks', 'foot slopes' or 'valleys' based on their geometry. Therefore, the forms were generic and descriptive and did not explain the origin of the landforms as geomorphology typically does, e.g. in 'glacial valleys'. Rather than that, the methodology allowed for delineation of forms for large areas beforehand, in case topology was integrated as an additional layer in applications such as hydrology or mapping potential disaster zones.