New trends in digital terrain analysis: landform definition, representation, and classification

This article provides an ontological as well as methodological evaluation of recent progress in terrain analysis. It focuses on six topographic factors, or existences, that are important in characterizing the biophysical functions of topography: elevation, surface shape, topographic position, topographic context, spatial scale, and landform object. Terrain analysis approaches are assessed according to what they really deal with, as well as how they work. Important trends are consequently identified, in which spatial scale plays critical but non-uniform roles. An index-based approach to the compound function of multiple topographic existences is recognized as successful in modelling surface/subsurface moisture and mass movement potential, but not mountain temperature. A classification scheme categorises defined landforms in the literature according to the way they exist in human knowledge rather than their morphological properties and derivation methods. Five categories are outlined: bona fide objects, prototypical objects,fiat objects, landform classes, and multiscale objects. Peak object delineation is lastly assessed as an example demonstrating some of the recent trends in terrain analysis. Representations of higher-scale landscape context are identified to have great potential of linking vastly different spatial scales, as well as bridging field- versus object-based treatments of the terrain surface.