GIS Watermarking: Hiding Data in 2D Vector Maps

Advancements in GIS map copyright protection schemes - a critical review

“…Table 2 outlines the major differences between vector data and image data in the context of digital watermarking applications [84,89,111,169].…”

“…The blocks-based embedding approaches divide the vector map into a number of parts (blocks) which help in achieving more robustness against noise and simplification attacks [111]. These approaches can maintain the fidelity of the watermarked vector map to some extent, and relatively locate the watermark bits in a certain block [204].…”

“…Consequently, the sequence of vertices' coordinates can also be considered high correlation data [83]. Since higher correlation means lower distortions and higher capacity, the difference between two adjacent vertices is used as embedding space [111]. The quantization modulation strategy is a nonlinear method used to hide the watermark and scale some map objects to derive the watermarked data [68].…”

“…Semi-fragile schemes allow the detection of malicious tampering with the vector map data [36,118,191]; in these schemes, the watermark is still detectable after non-malicious transformations, however, it is not detectable after malicious attacks. A successful attack refers to the success in removing the embedded watermark while preserving the validity of the vector map data [111]. In literature, the attacks can be classified in two categories: (a) geometric attacks [30,170,181], and (b) signal operation attacks [158,169].…”

“…Cropping refers to the process of cutting some parts of the map. For vector maps, such attacks are virtually reversible transformations of coordinates where almost little or no information would be lost [111]. Signal operation attacks can be simplification, interpolation and reordering operations, or noise addition [158,169] -see Table 10.…”