Research on quantification model for elevation point's terrain information based on DEMs

For a given point embedded in grid DEMs,its comprehensive quantification model of terrain information content representing its significance in approximating the true terrain surface is constructed on the basis of information theory after its terrain syntactic information content is measured with differential geometry algorithm,and its terrain semantic information content is determined according to the terrain feature type and the global terrain structure.Then,choosing a study area of 70 km2 in the loess gully region with a resolution of 5 m,the paper discusses the extraction procedure of the terrain information content for a grid point based on grid DEMs and an application in multi-scale terrain generalization based on grid point's terrain information content.Experimental results show that the terrain information measurement model for a grid point is feasible and the multi-scale DEMs reconstruction method is not only easy to implement but also effective in reducing terrain distortion by preferentially keeping a set of surface-specific structural points located in global terrain skeletons.The application example proved that the multi-scale DEMs constructed by selecting critical points based on their terrain information content values could meet the demands of digital terrain modeling in different terrain scales.Therefore,the research could be helpful in deepening our understanding of DEM terrain information characteristics and offering a theoretical and methodological support for multi-scale digital terrain modeling.