World Wide Web(WWW)上矢量地图数据的多分辨率传输算法

An Algorithm for Progressive Transmission Vector Map Data over the WWW

提出一种用于网络环境下多分辨率传输矢量地图数据的算法,此算法采用“点删除”技术用于多分辨率描述原始的矢量地图数据,而且能够避免空间对象的自相交和维护拓扑关系的一致性。以此算法为基础开发了一个Client/Server结构的实验软件,在实验结果的基础上评估了该算法对提高网络环境下矢量地图数据传输效率的效果。实验结果表明该算法用于矢量地图数据的多分辨率快速传输是有效的。

This paper investigates the benefits of progressive transmission of vector data, through designing and developing an algorithm for progressive transmission vector map data over the internet. The aim of the algorithm is to extract a coarse vector data set using vertex removal operations. Furthermore, a set of rules are proposed to control the validity of topology for the ＇coarse＇ vector data version, and a recovery algorithm is developed to reconstruct the ＇finer＇ vector data on the client side. The proposed method reconstructs the original data. The overall procedure is to （a） extract coarser data version on the server side on-line; （b） transmit coarser data version to the client; and （c） progressively recover more detailed data on the client side. An experimental prototype system has been developed to test the performance of the proposed method and illustrate its strengths and weaknesses. The experimental results show that the method can efficiently simplify spatial data, maintain the shapes characteristics of objects during transmission, and improve transmission time over internet greatly.