This paper discusses a watermarking method towards keeping robustness and high accuracy of vector graphics. The graphics is treats as a set of curves in the embedding algorithm

and each curve is divided into several shorter curves under a given threshold. And then a watermark bit combined with user certificate is embedded into each segment around the node for every cutting curve. To extract the watermark

it also divides up the watermarked graphics according to the division of the original graphics. Then

it extracts the watermark bit from each curve with the inverse procedure of the embedding process. Finally

the method calculates the similarity between the original watermark bits and the extracted ones from the watermarked graphics

and determines whether the watermark exists or not. The experiment results showed that the method not only guarantees the accuracy of vector graphics but also prossesses good robustness

such as it gives 100 similarities under no attack or only geometric transformation with the map; the anti-cropping ability gives 0.9 even for the graphics cropped 2/3. And it also has the ability of anti-compression of D-P approach and the experiment curve of the similarity threshold given which helps to control the anti- attack ability of watermark and set parameters for an automatic procedure of watermark detection.