基于Visvalingam-Whyatt改进算法的线要素化简

线要素化简对空间数据存储、传输和表达具有重要意义。现有方法的化简效率和空间关系维护是一个矛盾体,为提高化简效率的同时解决化简结果中线要素自相交问题,提出基于Visvalingam-Whyatt改进算法的线要素化简方法。以排序列表键值对的形式记录有效面积和节点标识,再利用给定的保留节点数重新构建线要素,在重构过程中逐点进行自相交判断,并通过前插或移除节点的方式解决自相交问题。以1∶100万比例尺的海南岛海岸线为研究对象进行化简实验,结果表明本文所提算法能够解决线要素自相交问题,且具有较高的化简效率。该方法可为其他线要素化简算法提供自相交解决思路。

A line simplification method based on improved visvalingam-whyatt algorithm

Line simplification is of great significance to the storage,transmission and expression of spatial data.However,the existing method can hardly be carried out with the simplification efficiency and the maintenance of spatial relationship.As it aims to improve the simplification efficiency and solve the problem of the self intersection of the middle line elements in the reduction results,a new method of line element reduction based on the improved Visvalingam-Whyatt algorithm is proposed.To begin with,the effective area and node identification are recorded in the form of sorting list key value pairs,and then the line elements are reconstructed by using the given number of reserved nodes.In the reconstruction process,the self intersection judgment is made point by point,and the self intersection problem is solved by inserting or removing.The experimental results authenticate the effectiveness and superiority of the proposed method with self intersection and a high efficiency of simplification.The method can provide self intersecting solution for other simplification algorithms.