Determination of dissection index (di) using GIS & RS techniques

Anotace: Advances in Remote Sensing (Digital Elevation Models) products and GIS techniques have made the calculation and analysis of morphometric indices much more accurate, effective, and less time-consuming. Dissection index (Di) is a morphometric parameter that indicates the degree of dissection or vertical erosion and the stage of landform development. Calculating morphometric parameters by manual methods is inconvenient because it takes a long time, is subject to mistakes that can be made by humans when extracting these parameters and, consequently leads to wrong conclusions. There is currently no fully automated method to calculate this parameter. The purpose of this paper is to define the procedures for extracting this parameter within a GIS environment using data from high resolution (HR) ALOS-PALSAR (Advanced Land Observing Satellite-Phased Array-Type L-band Synthetic Aperture Radar) Radiometrically Terrain Corrected (RTC) DEM with a spatial resolution of 12.5 m with the help of ArcGIS software. To calculate this parameter, a grid with 1x1 km cells with interpolation points in each cell was constructed. IDW was chosen as the most suitable method for the interpolation of points. Based on the obtained results, the extreme values of Di for the Drenica River basin ranged from 0 – 0.46. 90.54% of the surface belongs to the low and very low values of Di, 9.11% belongs to the average values while only 0.35% belongs to the high values of Di. The high participation of small values of this index for the Drenica River basin indicates that river erosion is very low and the total area is increasing towards the creation of flat surfaces. The relief dissection index can be used for various purposes, such as contributing to a better understanding of the spatial distribution of morphogenetic processes, relief segmentation, and landscape units that serve as the basis for geomorphological mapping work, study the balance between pedogenesis and morphogenesis, and the assessment of environmental vulnerability.