面向移动导航设备的数字地图分级组织与预取策略

由地图数据的分级组织出发,提出一种基于多级Hilbert网格的地图数据组织与预取策略．通过多级Hilbert网格的二进制编码，使网格之间层次关系和邻近关系的刻画更加准确和灵活,而分级的数据组织，更加符合地图显示的现实情况，降低了数据预取和更新操作的代价．测试表明该策略优于普通的预取策略，并已在上海市交通信息网格移动信息终端的研发中取得了良好的实施效果．

Hierarchical Digital Map Data Management and Prefetching in Mobile Navigation System

Beginning with the hierarchical data management, this paper presents a data prefetching and updating strategy based on Hierarchical Hilbert Grid. Through the binary coding, the hiberarchy relationship and neighborhood relationship are described more exactly and flexibly. At the same time, the hierarchical data management is more suitable to the practical map display and can further decrease the cost of data prefetching and updating. The test result shows that such a strategy is more excellent than the ordinary prefetching methods,