Digital vector maps are used in several
applications, such as car navigation system, web-based map services, geographical information system (GIS), and computeraided design (CAD). As with any other digital data, digital maps are easy to update, duplicate, and distribute. As a result, illegal operations such as forgery and redistribution of the maps can be done equally easily. Therefore, the application of digital vector maps faces a number of challenges including copyright protection, data authentication, and data source tracing. These issues are problematic and limit the use of digital vector maps. Digital watermarking has been proposed as the solution to these problems. However, recent literature review in this field suggests that most of the watermarking schemes for digital vector maps in the literature do not take into account the preservation of the
map topology which is important in preserving the integrity of the map. Furthermore, most techniques lack the features to
control the distortions. In this paper, we propose a novel watermarking algorithm for copyright protection of digital
vector maps that takes into account the preservation of the map topology after embedding the watermark operation as well as
provides the users a means to control the distortions. The technique works by inserting additional vertex coordinates
between adjacent vertices which locations are governed by the value of the watermark data. Our experiments have shown that
our proposed technique is robust against all geometric attacks, format exchange attacks, and additive noise attacks.