Spectral geomorphometric variables: the computation and using in the landform mapping

Abstract

A methodology for calculating eight spectral terrain characteristics by DEM is given. Their geomorphological meaning and mathematical definition are described. The generalized results of the spectral terrain characteristics calculation for five continents (except for Antarctica and a number of large and small islands and archipelagos) by DEM with a resolution of 1000 m, a step of a moving window of 10 km and its various sizes from 40 to 100 km are presented. The total covered area was 119.3 million sq. km. The results of the continents landform clustering on a small scale by its periodicity are shown – 10 clusters are distinguished using Kohonen neural networks and subsequent hierarchical clustering, which separate different patterns of topographic dissection. The spectral characteristics of the relief that distinguish various areas reflect the typical elevation difference between the watersheds and the bottoms of the valleys, their frequency in space, the unidirectional or multidirectional oscillations of the altitude field, and the prevailing direction itself, etc. Corresponding general map is made.