The Impact of Surface Complexity on Derived Topographic Properties from a Grid-based Digital Elevation Model

摘要

This paper studies the relationship between terrain complexity and derived topographic properties from grid-based digital elevation models (DEM). The impact of terrain complexity represented by terrain steepness and orientation on derived parameters such as slope and aspects has been analysed. Experiments have also been conducted to quantify the errors created by digital terrain analysis algorithms. The test results show that (a) the RMSE of derived slope and aspect is negatively correlated with slope steepness; (b) the RMSE of derived aspect is more sensitive to terrain complexity than that of derived slope; and (c) the errors in derived slope and aspect tend to be found in flatter area, and decrease with increasing terrain complexity. The study shows that although primary surface parameters can be well defined mathematically, the implementation of those mathematical models in a GIS environment may generate considerable errors related to terrain complexity. In general, when terrain is rugged with steep slopes, the error of derived parameters is quite minimal. While in a flatter area, the derived parameters, particularly the aspect, may contain considerable amount of errors, causing significant limitation in applying the analytical results.