MATLAB functions for extracting hypsometry, stream-length gradient index, steepness index, chi gradient of channel and swath profiles from digital elevation model (DEM) and other spatial data for landscape characterisation

Abstract

The landscape, developed by the interaction of geological processes, is represented by Digital Elevation Models (DEMs) of various spatial resolutions. These DEMs can be variously analysed for the spatial and linear morphometric indices for landscape characterisation. We have developed MATLAB functions for extracting Hypsometric integral (Hi), Stream Length-gradient (SL) index, Normalized steepness index (ksn), Chi (χ) gradient index and Swath profile with maximum, minimum and mean elevation profiles from DEM. These functions are tested on SRTM DEM (30 ​m, 90 ​m spatial resolution) and ASTER GDEM (30 ​m spatial resolution) from three different catchments with varying tectono-geomorphic setup. The swath profile of the TRMM precipitation data is also prepared to demonstrate the application of present functions on different raster dataset and their robustness for multi-parametric correlations. The user-friendly MATLAB functions provide automation and flexibility to extract the morphometric indices cited above from DEM and other raster data with user defined variables for different tectonic-geomorphology and environmental studies.