Abstract: This paper hides the watermark information into the curve shape characteristic set using Quantized Index Modulation（QIM） based on variable quantization step.At the same time，the watermark bits scatter across the whole dataset by Hash mapping and bits repeated insertion.Results show that the curve shape distortions have been well controlled，and robustness to the threatening watermark attacks，such as vertex attack，data simplification，and feature deletion and so on，has been proved.

Key words: vector map data, digital watermarking, curve shape, Quantized Index Modulation（QIM）, fidelity, robustness

摘要： 提出一种矢量地图数据水印模型，利用量化索引调制（QIM）思想，基于变长量化步长，将水印信息隐藏于有效表征曲线形状的特征集合中，在保障算法鲁棒性的前提下，很好地顾及了曲线的形状变形。同时，通过数据哈希分组及水印重复嵌入的方式，将水印信息散布到整个数据集。实验结果表明，该算法在水印的不可见性方面有明显改进，并且在抵抗节点攻击、数据化简及地物删除等很具威胁性的水印攻击方面也具有令人满意的鲁棒性。

关键词: 矢量地图数据, 数字水印, 曲线形状, 量化索引调制（QIM）, 保真度, 鲁棒性