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Watermark Embedded in Polygonal Line for Copyright Protection of Contour Map

Summary In GIS system, we often use vector contour map to show or locate position on the earth. Since such map data is very worthy of value, it is necessary and important to protect its copyright. In this paper, we propose a new method to embed watermark into the angle parameter of polygonal lines or curves in a contour map after its parameterization. The watermark can be detected as proof of the ownership or authority of the map by hypothesis test.