A new method for the lossy compression of segmentation maps is presented. In the first stage of the proposed algorithm, region boundary segments are coded, providing a coarse polygonal approximation of regions, as well as a complete representation of their adjacency. The second stage consists of the progressive refinement of these segments, until either the desired degree of accuracy is reached, or the target bit-rate is achieved. Rate-distortion curves demonstrate good lossy performance in the range of 0.3 to 0.6 bits per contour point.