海图等深线自动合并方法研究

提出了一种Delaunay三角网支持下的等深线自动合并方法。首先提出一种避免进行地形特征分析的待合并等深线探测方法，用于自动探测待合并的等深线；其次，通过三角形筛选构建桥接区域，并对桥接区域进行扩展、填"孔"操作；接着，利用Delaunay三角网在曲线弯曲识别方面的优势，提取待综合的弯曲区域；然后，合并待综合弯曲区域和桥接区域得到待综合部分，利用图形对称差分运算得到合并结果；最后对合并结果进行光滑处理。实验表明，该方法能够自动正确地对待合并等深线进行探测，合并结果不仅能够满足航行安全，而且图形形态清晰、光滑。

Study on Automated Aggregation of Depth Contour on Nautical Charts

An automated method for aggregating depth contour based on triangulation is proposed. Firstly, an automatic method to detect aggregating contours is proposed, which doesn't need to reco-gnize the submarine topography features. Secondly, triangles to construct the bridge areas are filtered, and the bridge areas are expanded and related "holes" are filled. Next, the bend areas to generalize are detected. Then generalized areas are derived by merging the bride areas and generalizing bend areas, and then the aggregated result contours are achieved by conducting symmetric difference calculation on the boundary of generalized areas and the aggregating contours. Test results show that the method proposed in this paper can detect the aggregating contours correctly, and the aggregated results not only can guarantee navigation safety but also can achieve a legible and smooth depth contour.