Protecting GIS vector map using the k-means clustering algorithm and odd-even coding

For protecting the copyright of GIS vector map, this paper present a watermarking scheme based on polygon type of ESRI by using k-means clustering algorithm. This watermarking scheme use k-means clustering algorithm to make all polygons into some clusters. Then we embed a watermark bit to the mean distance length of each polygon in a cluster by using odd-even coding. Finally, we change the coordinates of vertices according to the new mean distance length of polygon which has been embedded watermark. From experimental results, we verify that the proposed scheme has outstanding invisibility and good robustness against various geometric attacks.