Blind watermarking scheme for polylines in vector geo-spatial data

With the rapid development of GIS and computer technology, the geo-spatial data has been widely used in many fields. Since the production of geo-spatial data is very costly, illegal copying will lead to huge loss of the data owner. In order to protect the copyright of geo-spatial data, digital watermarking has been employed in recent years. In this paper, current works on geo-spatial watermarking and cardinal attacks are analyzed. Consequently, a blind watermarking scheme for polylines in vector geo-spatial data is proposed. In the proposed scheme, FVDR (feature vertex distance ratio) is constructed based on the feature vertices of polylines. As the cover data, FVDR is slightly modified through quantization index modulation to embed the corresponding watermark bit. Each bit in the watermark is embedded in several polylines, by doing so each of these polylines contains a copy of the corresponding watermark bit. Because of the specially designed cover data, quantization modulation and redundant embedding, the proposed scheme is robust to geometrical attacks, vertex attacks and object attacks. Also, the results of extensive experiments demonstrate the robustness of the proposed scheme.