Two-dimensional vector data compression method

The method divides original vector data into blocks of vector data. Next, loss compression based on DCT transform is carried out for the blocks of vector data according to one of two modes. Then, entropy coding is carried out for the obtained DCT transform so as to obtain compressed blocks of vector data. Finally, all compressed blocks of vector data are organized as binary bit steam in specific format. Main effects of the invention are: compression ratio near to 20 is reached for vector data formed natural in wide range such as contour line, road network and water system etc; SNR reaches to 60dB; and maximal absolute deformation is about 10-5 order of magnitude of dynamic range of original vector data. Features are: controllable distortion generated in reconstructing error and compression process; providing technical base for asymptotic transmission of vector data flexibly and in high efficiency by combining asymptotic compression technique in space domain and in frequency domain.