Pemetaan Kemiringan Lereng berbasis Data Elevasi dan Analisis Hubungan Antara Kemiringan Lereng dengan Bentuklahan.

Abstract

Slope is part of a landform determined by various factors which derived from endogenic and exogenic geomorphic processes. Topographic map is one of the most frecuently used data for slope steepnes mapping. Elevation data from satellite record such as Shuttle Radar Topography Mission (SRTM) or others recently also used to build topographic data. The aim of this research are (1) slope steepnes mapping based on Indonesian Topographical Map (Rupa Bumi Indonesia or RBI) scale 1:25.000 and SRTM, and (2) landform mapping and analysis for landform and slope relationship. The Cileungsi Watershed was selected for research area since it has various landforms. Mapping method was done visually for printed RBI, whereas for digital RBI and SRTM data were done digitally using geographic information system software (ArcGIS). Stratified random sampling approach has been used for field work upon interpertated landform and slope analysis maps. The result show that the widest slope class in Cileungsi watershed was quite different for each method. By visual method mapping (printed RBI), the widest slope steepnes was B-class (32%), as for digital RBI was A-class (41%), and for SRTM data was C class (35%). To know where the similar slope steepnes classes having the same spatial location (overlap), the overlay processes have been done between 3 slope steepnes maps i.e. derived from printed-RBI, digital- RBI, and digital-SRTM. By these operations, it reveal that the average of overlap area were 38% for visual-RBI vs. digital-RBI, 50% for digital-SRTM vs. digital- RBI, and 59% for digital-SRTM vs. visual-RBI. Thus, the latter comparasion indicated the better one in common results. Geomorphologically, Cileungsi watershed composed by 17 types of landforms where the denudational-claystone hills, was the widest landforms in study area (18,18%). In relation to the slope steepnes, the morphography of plains were generally characterized by A and B slope steepnes classes; for the river valley, such as floodplain & terraces were characterized by A-class, but for the river valley of upper slopes (in hilly and mountainous areas) were characterized by C and D-classes. For hills morfography, the characterized of dominant slope varies from B to D-classes and so did for mountains morfography. However the typical characteristic of hilly or mountainous landforms were the heavier of incision the greater of slope steepnes class.