A Study Of The Lossless Compression Algorithm Of Vector Map Data

Aimed at some kinds of restriction which make the storage and transportation of vector map data in the fact of the data and the bandwidth, the lossless compression algorithm of vector map data are studied in this dissertation. By improving the universal lossless compression algorithm, the dissertation brings forward a lossless compression strategy of the vector map data that uses the geometry compression and the universal lossless compression synthetically, realizes the lossless compression algorithm of the vector map data, it can guarantee this algorithm highly effective and accurate on the compression rate and the compression ratio. The main points of this dissertation are as follows:1. Base on synthetically analysis of development status on the compression algorithm of the vector data and the universal lossless data, elaborates the principle and methods of lossless data compression comprehensively, analyses their advantage and disadvantage.2. Studies the coding principle and coding process of the typical algorithms of the universal lossless compression algorithm—Huffman, LZSS, LZW. Analyzes and compares the property and the characteristic on compression time, compression ratio and the complexity of these three algorithms. A kind of appropriate algorithm—LZW algorithm is choosen from them.3. Based on in-depth analysis of the storage characteristic of the vector map data, brings forward a lossless compression strategy of using the geometry compression and the universal lossless compression synthetically. According to the different saving characteristic in geometry files, the dissertation studies a kind of efficient geometry lossless compression algorithm. At the same time, aimed at the shortage of LZW, the dissertation improves it. The experiment data proves that this algorithm can get a good compression efficient.4. Combines with the task need, designs and realizes the experiment and analysis system of lossless compression of the vector map data, this system approves analysis of compression rate and compression ratio, etc.