DEM generalization with profile simplification in four directions

The DEM generalization is the foundation of expressing and analyzing the terrain and the basis of multi-scale observation. Meanwhile, it is also the core of building the multi-scale geographic database. This paper would like to propose a new algorithm using profile simplification in four directions(4-DP). This algorithm is composed of two parts, namely extraction of terrain feature points in local window as well as in global profile line and reconstruction of DEMs. The paper used the 5 m resolution DEM of the Suide in Loess Plateau of China as the original data. In the experiment, this paper has achieved the generalized DEM with 5 m and 25 m resolution by removed small details and computed out the optimal threshold. In contrast to the classic algorithms, VIP and Aggregate, based on three evaluation methods. The results show that this method is able to retain the main geographical information effectively in terrain surface.