Digital Elevation Models

Digital Elevation Models (DEMs) are useful digital representation of earth¿s topographic relief that has developed as a result of interaction of earth¿s internal and external process, over a long temporal scale. However, accuracy of the extracted information and parameters highly rests on the quality (resolution) of input DEMs. Therefore, this book is presented to study a comparison between 30m-ASTER and 90m-SRTM DEMs is carried out in order to ascertain their suitability and accuracy for geomorphological analysis. A comparison is also done with SRTM 90 resampled to 30m to emphasise the importance of resolution, where in the extracted parameters were found to be similar to that obtained with that of ASTER 30 DEM. Geomorphological parameters related to drainage patterns and basin morphology have been compared over varying topographic relief. Besides the resolution, the thresholding of the flow accumulation or drainage area was also found to strongly control the morphometric results, which was in turn controlled by the resolution of the DEM.