基于JPEG2000无损压缩的DEM网络渐进传输方法

针对网络GIS海量DEM数据与有限带宽之间的矛盾,根据DEM数据特点和网络多分辨率渐进的应用需求,提出了一种在DEM各级分辨率具有良好精度性能、基于改进的JPEG2000高效无损压缩的DEM网络渐进传输方法。选用2/6整数小波分解DEM数据,利用辖区渐进压缩方法、压缩码流的索引文件检索码流实现了DEM的渐进传输。实验证明,2/6小波比标准中的5/3小波能够更好地在每级分辨率保持原始地形精度,相比传统方法,网络渐进传输时每级分辨率传输的数据量平均减少了90.29%。

Progressive Transmission Method of DEM Data Based on JPEG2000 Lossless-Compression

According to the DEM data characteristics and the application needs of DEM network progressive transmission,a new progressive transmission method of DEM data based the improved JPEG2000 lossless-compression is presented.With this method,the accuracy of DEM data's accuracy in each resolution can be hold perfectly and the data can be compressed effectively and progressively.The 2/6 integer-to-integer wavelet basis is used to decompose DEM data.Using the precincts progressive compression method and the index file of the compressed code stream,the progressive transmission of DEM data is realized.It is proved that the original terrain characteristics are better maintained at different resolutions compared to the standard 5/3 wavelet basis.The transmitting data bytes are decreased to 90.29% compared to that of the traditional method in network progressive transmitting.