A New Algorithm for Watermarking Building Polygons

GIS data is of great value. The high cost of GIS data acquisition and the ease of data exchange via networks make the protection of distributed data sets a crucial issue. To resolve this kind of issues, many digital watermarking algorithms for vector digital maps have been proposed. However, most existing algorithms donpsilat fit the building layers because of the ignorance of the distinguish characteristics of the building polygons, such as the relatively much fewer vertices and the right angles. To watermark the building layers , this paper proposes a new algorithm which takes into account the right angles and avoids the dependence on the vertices density by modulating the watermark sequence into the objectspsila spatial relations. The experiments show that it is an effective and robust algorithm.