A Shape-Based Vector Watermark for Digital Mapping

Abstract

Digital vector maps are an expensive commodity. Like any digital data, they are also very easy to copy. Piracy (or unauthorised reselling) of maps will become increasingly common in the future. This project looks at embedding a hidden message or watermark in a digital map so that its original authorship can be ascertained. This information enables a 3rd party to verify a seller's rights to the map and aid in the resolution of copyright disputes. Some other vector watermarking schemes, look at vector maps as a cloud of coordinates, to be perturbed in some way that is independent of actual usage. These papers generally do not discuss how large a subset of the map is needed to reliably retain the watermark. Instead, we concentrate on watermarking map feature lines, so that feature extraction from a watermarked vector map may not necessarily compromise watermark integrity.