Color maps and graphs compression

Color maps and graphs are widely used in a variety of applications such as mobile computing, intelligent transportation systems, GIS, Internet, and academia. The relatively large size of color maps and graphs has negatively impacted their usage in many applications especially in small storage mobile wireless devices. To meet such requirements, the use of efficient compression methods becomes imperative. In this paper, a fast lossless compression scheme for digital map and graph images is introduced. This scheme offers two contributions. The first is the creation of a universal codebook that is based on symbol entropy and the second is our row-column reduction coder. The experimental results show that the proposed scheme achieved on average a compression of 0.035 bpp for map images and 0.03 bpp for graphs. These results are better than those reported results in the literature.