Identification of topographic elements composition based on landform boundaries from radar interferometry segmentation (preliminary study on digital landform mapping)

Abstract

Abstract. Dense vegetation that covers most landscapes in Indonesia becomes a common limitation in mapping the landforms in tropical region. This paper aims to examine the use of radar interferometry for landform mapping in tropical region; to examine the application of segmentation method to develop landform type boundaries; and to identify the topographic elements composition for each type of landform. Using Idrisi® and "eCognition ®" softwares, toposhape analysis, segmentation and multi-spectral classification were applied to identify the composition of topographic elements i.e. the types of land-cover from Landsat 8, elevation, slope, relief intensity and curvatures from SRTM (DEM). Visual interpretation on DEM and land-cover fusion imagery was conducted to derive basic control maps of landform and land-cover. The result shows that in segmentation method, shape and compactness levels are essential in obtaining land-cover, elevation, and slope class units to determine the most accurate class borders of each element. Despite a complex procedure applied in determining landform classification, the combination of topographic elements segmentation result presents a distinct border of each landform class. The comparison between landform maps derived from segmentation process and visual interpretation method demonstrates slight dissimilarities, meaning that multi-stage segmentation approach can improve and provide more effective digital landform mapping method in tropical region. Topographic elements on each type of landforms show distinctive composition key containing the percentage of each curvature elements per area unit. Supported by GIS programming and modeling in the future, this finding is significant in reducing effort in landform mapping using visual interpretation method for a very large coverage but in detail scale level. IntroductionThe application of remote sensing in geomorphic mapping has been developing vastly, coinciding with the launching of radar interferometry and its ability to provide digital surface/elevation model (DSM/DEM) [1]. One of the important parameters in geomorphic mapping is land physical characteristics information derived from landform classification and mapping, both in regional or global level. Landform, as the main element in geomorphic mapping, is a natural object feature that divides the earth surface into one main spatial unit [2]. It comprises the information of relief, elevation and the common land activities that dominating the landscape processes. DEM provides more promising data to the researchers in increasing the quality of landform mapping, because it consists of elevation information with 3-dimentional relief features. Nowadays, landform classification using DSM/DEM is one of basic research domain in digital terrain analysis, including GIS landscape integrated studies. The common free access and reliable 3-dimentional relief data used in many mapping applications is Shuttle Radar Topography Mission (SRTM) (Figure 1). This imagery has horizontal and vertical spatial ...

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