Comparing data acquisition methodologies for DTM production

In this paper we present the results related to several field campaigns conducted in the last three years in a small (4.4 km2) wilderness basin in Carnia, a tectonically active alpine region in northeast Italy. The study area is a typical alpine debris-flow dominated catchment where several landslides, including a significantly large one, were observed and mapped. The field survey carried out in 2007, 2008, 2009 and 2010 were focused on the large landslide of the basins and they consisted in the following steps: 1 – development of an accurate GPS network, 2 – make use of a long range Terrestrial Laser Scanner (TLS) for a detailed and local analysis of landslide movements, 3 – merge the data with an airborne LiDAR for a large scale analysis of the processes. Preliminary analysis consist in the comparison of different high resolution Digital Terrain Models (DTMs) in order to estimate the debris volume that has been triggered during the last movements of the landslides. Achieved results show that the integration between ALS and TSL data allows to produce DTMs of limited extent, with higher quality and level of detail. Such DTMs improve the capabilities for landslides analysis and modelling with respect to the use of LiDAR data only, even in areas providing limited or difficult access for the survey activity