Modelling terrain complexity

Abstract

Terrain complexity is an important terrain feature in digital terrain analysis; however, unlike aspect or slope, terrain complexity is an ambiguous terrain feature that until now has had no optimal index to quantify it. The traditional terrain complexity definitions can be classified as statistical, geometrical, and semantic indices. These indices evaluate terrain complexity only from one perspective of geomorphometry, and will cause more or less prejudice when modelling the real world. This chapter wants to seeks an optimal terrain complexity index (TCI) based grid DEM. Firstly, we select four traditional indices (total curvature, rugosity, local relief, local standard deviation) that can easily be evaluated by a local kernel window, then deduce the compound terrain complexity index (CTCI) using the normalization factor. In order to validate the CTCI, four study areas with typical terrain characteristics of plane, gully, hill and hybrid landforms are selected for experimentation. The results show CTCI to be a sound terrain parameter to evaluate terrain complexity. Terrain complexity is a regional feature, while CTCI is a local index, so the statistics (Mean CTCI, Maximum CTCI, and SD CTCI) are proper indicators to statistically evaluate terrain complexity.