基于DEM的地形简化方法对比分析

Contrastive Analysis of Methods of Terrain Simplification Based on DEM

地形简化作为一门重要的数据压缩技术已广泛应用于DEM。在大量简化算法中,地形简化指标作为地形简化的核心环节,其好坏直接关系到地形简化的好坏。本文对基于局部误差、曲率和法向量的五个地形简化指标进行了分析评价,用离散的高斯合成曲面来模拟真实DEM,以解析得到的高斯曲率作为地形简化指标“真值”,对比研究了在离散高斯曲面上得到的五个简化指标与解析所得“真值”,通过对各个指标“保特征性”可信度的分析,获得了对这五个指标的整体评价,最后,实例验证了本文结论的正确性。

Terrain simplification algorithms are widely applied to digital elevation model as an important technology of compressive data. How well the effect will be acquired depends upon terrain simplification index, which is one of core parts among these algorithms. This paper analyzes five indices, which are based on local error, curvature and normal vector and gains their estimate of capability of preserving terrain characteristic. Firstly, we construct gauss mesh, which is used to simulate real terrain by gauss equation and calculate gauss curvature of each grid point, which is regarded as true value to terrain simplification index. Secondly, reliabilities to preserve terrain characteristic are obtained by comparing these indices with gauss curvature. We gains macro-estimate of the five terrain simplification indices by analysing their reliabilities and so do when changing gauss mesh’s shapes and resolutions. Finally, we testify research result based on a lot of real terrain and find that it is all right.