Terrain Simplification from Grid DEMs Based on Local Moran’s I Index

Terrain simplification algorithms from grid DEMs of high resolution offer an effective solution for constructing multi-scale DEMs. This paper presents a simple method for simplifying terrain from dense grid DEMs based on a grid cell’s spatial autocorrelation. A simplified DEMs is reconstructed by calculating local Moran’s I index for DEM cells with terrain feature points obtained with an appropriate Moran’s I threshold value. The effect of reconstructed DEMs was evaluated for a test site in an area in loess hilly-gully region with 5 m DEMs.The values for elevation statistical parameters，the structure of terrain feature lines and slope values are aquired from the DEMs reconstructed by the local Moran’s I index and very important points(VIP) algorithm.Experiment results with a comparison to the VIP method show that the proposed algorithm is clear easy procedure，and highly efficient;it delivers near-perfect precision retaining the geo-morphological skeleton by analyzing spatial distribution of surface-specific structural points used to reconstruct new DEMs.