A new watermarking method for vector map data

In this paper, we propose a new digital watermarking method for protecting of vector data in geographic information systems. The method is based on a combination of two novel approaches. Firstly, the watermark information is embedded into the polygon map objects by cyclically shifting the list of vertices of each polygon. Secondly, instead of a bit vector, a raster image superimposed on the map is considered as a watermark. The major advantage of this method is that it does not distort the map by altering the coordinate values. A simple example demonstrates the method efficiency, as well as the robustness of the embedded watermark against geometric transformations usually performed when working with map data: translation, scaling, rotation and cropping.