基于2维行程的栅格数据快速动态压缩算法

Fast Dynamic Compressing of Raster Data Using 2D Run-Length

分析了常规2维行程压缩算法存在的不足,在此基础上提出了一种在遍历栅格数据过程中直接快速动态生成2维行程的栅格数据压缩算法。该算法以MD码代替行列号来扫描栅格数据,对于一个2×2的窗口由MD码反解行列号只需转换左上角格网单元,同时以动态线性表代替静态线性表。在提取栅格单元的过程中,直接检测对比格网单元的属性值,动态分配内存来建立2维行程编码。最后,大量实验表明,算法在运行效率和内存占有量方面均优于常规的2维行程压缩算法。

Due to some disadvantages of the traditional 2D run-length compressing, a fast dynamic compressing of raster data using 2D run-length is put forward in this paper, The method can construct 2D run-length directly through only once tracing of the whole raster data, Firstly, it scans raster data by the decimal Morton code instead of the row, and once uses a 2 × 2 window to extract 4 sequential pixels from the original raster data, Secondly, it uses a dynamic linear table instead of a static table. Transforming the attribute value of the pixels, it directly compares among their attribute values, and dynamically makes 2D run-length. Finally, the some experiments show that this algorithm is superior to the traditional 2D run-length compressing in the running speed and memory requirement.