Delaunay三角网支持下的海图等深线化简

Chart Depth Contour Simplification Based on Delaunay Triangulation

等深线化简是海图综合的重要研究内容。针对现有化简方法存在的化简弯曲识别不准确、化简不彻底等问题,提出了一种Delaunay三角网支持下的等深线化简算法。首先,对等深线构建约束Delaunay三角网,实现了等深线弯曲结构的二叉树表达;其次,基于约束Delaunay三角网结构,改善了等深线上需要化简弯曲的识别方法;最后,设计了多种化简手段,建立了新的等深线化简模型,实现了对等深线形状的彻底化简。实验结果表明,化简结果能够满足航行安全要求,等深线的主要弯曲特征得到了有效保持和清晰表达,化简精度符合制图要求,且能够有效避免自交。

Automated depth contour simplification is one of the common studying content in chart generalization.There are some problems such as inaccurately recognized bends and incompletely simplified bends in existing simplification methods.To overcome the drawbacks,a simplification method based on constrained Delaunay triangulation(CDT)is proposed.Firstly,CDT is constructed to achieve the binary tree representation of depth contour.Secondly,detection of bends which needs to be simplified is improved based on CDT.Finally,variety of generalization tools are designed and a new simplification model is built to realize the complete simplification of bends on depth contour.Tests illustrate that the proposed method meets navigation safety requirements,and the main bend characters are retained and represented clearly.The position accuracy meet the request of chart production.Besides,self-intersect can be avoided validly.