The Globe DEM Parameterization of the mountain features of Minor Asia.

Abstract

In previous research efforts, methodologies were developed for the extraction of mountains from the GTOPO30 digital elevation model (DEM) in Basin Range and in Zagros Ranges (Iran). On the other hand the evaluation of the parametric representation (mountaintop accuracy assessment) of mountains revealed systematic errors in the GTOPO30 DEM. Here, the extraction of mountains within the Minor Asia is presented. The GLOBE DEM is used, that is the most thoroughly designed, reviewed, and documented global DEM today. The study area is bounded by latitude 36 to 42 N and longitude 26 to 45 E approximately. More specifically, region-growing segmentation was implemented and ridge pixels were considered as seeds while the growing criterion was based on gradient. Valley pixels did not allow participating in the region growing process for region growing to be blocked in NE were steep sloping valleys were evident. Small in size (less than 30 pixels) isolated islands of mountains were removed. Additionally, small islands (less than 24 pixels) of non-mountain aggregates (flat mountaintops) were merged to the mountain terrain class. The extracted 702 mountain objects were in accordance to the features interpreted visually from a shaded relief map of the study area. In a forecoming effort, mountains within Iran, Turkey, and Greece will parametrically represented on the basis of geomorphometric attributes and interpretation models will be provided for the Eurasian-Arabian continental margin on the basis of the morphometry of mountains. INTRODUCTION AND AIM Various research efforts tried to explore the relationship between tectonics and topography [Merits and Ellis, 1995; Summerfield, 2000) and various geomorphometric techniques (Pike, 1995, 2000) have been developed in an effort to automate the interpretation of terrain features from digital elevation models (DEMs). Towards this end a methodology was developed for the extraction of physiographic features from GTOPO30 DEM (US Geological Survey, 1998) and it was implemented in Basin and Range where the crust is under tensional forces, thins by normal faulting, and results in an array of tipped mountain blocks (Miliaresis and Argialas, 1999). In another effort, the mountains were considered to form the elementary morphotectonic units and a) their definition and b) modeling, could characterize the landscape at regional scale (Miliaresis, 2001a). Thus, a method was developed for the extraction of mountains in an area of compressional stress such as the Zagros Ranges (where collision of the Arabian shield with Iran has shortened and thickened the crust to produce a spectacular mountainous physiography) and the landscape of the study area was characterized on the basis of the resulting morphometry of mountains. Zagros Ranges is part of Alpine-Himalayan belt that is extended through Turkey to eastern Greece (Moore and Twiss, 1995). It would be of great scientific interest if the mountain ranges from Iran to Greece were extracted and represented by a set of numerical attributes and the landscape of the Eurasian-Arabian continental margin was characterized on the basis of the morphometry of mountains. On the other hand the evaluation of the parametric representation of mountains in Zagros revealed systematic errors in the GTOPO30 DEM (Miliaresis and Paraschou,