机构地区: 中国科学院遥感应用研究所遥感科学国家重点实验室
出 处: 《地理与地理信息科学》 2009年第4期22-24,29,共4页
摘 要: 海量地形数据给其存储、分发和实时渲染带来了极大的挑战,因此迫切需要适合网络环境下地形可视化的数据压缩方法。该文探讨地形复杂度与DEM压缩方法的关系,研究可视化中地形复杂度的计算方法,并提出一种改进的SPIHT小波压缩方法:采用小波分解后的系数对DEM的地形复杂度进行评估,并针对地形复杂度对编码算法进行自适应调节。实验证明,这种改进的SPIHT小波压缩方法采用合适的压缩比进行DEM数据压缩,能够在满足地形可视化需要的同时提高压缩效率。 Huge amounts of DEM data usually bring great challenge to DEM storage,transmission and real-time rendering. The DEM compression method of visualization in net environment is urgent to be improved. In this paper,the relationship between terrain surface complexity and DEM compression method is discussed, the calculation method of terrain complexity in visualization is researched,and an improved SPIHT compression method is promoted. In the compression method, the terrain surface complexity is evaluated using the coefficients after wavelet decomposition,and then the terrain complexity selbadaptation method is adopted to adjust coding algorithm. The experiment shows that the improved SPIHT wavelet compression method can adopt appropriate compression ratio to compress DEM data,and the compression efficiency can be improved with satisfying terrain data visualization effect.