Analysis of High Resolution Digital Terrain Model for Morphometric Parameters Extraction and Classification

A morphometric analysis of a high resolution digital terrain model (DTM) has been performed in order to define morphological features and classify landforms of "La Fossa" Cone of Vulcano Island (Aeolian Arc, Italy). The digital model with a grid size of 1X1m has been obtained by means of an automatic digital processing of digitized airborne stereo images. Maps of the four more important morphometric parameters (slope angle, aspect of terrain, profile curvature and plan curvature) have been extracted and analyzed. The visual interpretation of morphometric maps aided by a lithology map [Keller, 1980] and vegetation boundaries map, derived from aerial photos, a classification of landform based on terrain elemental units has been performed and graphically represented as a Terrain Units Map. Terrain units represent geomorphologically different units characterized by a predominance of certain surface processes and therefore certain landforms. Starting from morphometric parameters a Morphometric Units Map has been generated, and used to perform a study about the identification of terrain instable sectors. By an authomatic procedure in which morphometric parameters were the input variables, a terrain classification based on morphometric units has been derived. The classification process consisted on two steps, the classification of each slope factor into a few significant classes, stored into a single layer, and the sequentially overlaying of all the layers allowing to obtain homogeneous domains. The use of of high resolution DTMs in terrain analysis allows to perform very detailed morphometric alalysis to derive terrain units and slope surface boundaries maps.