摘 要:目前对矢量数据分布式拓扑关系的研究较少,且矢量拓扑表示方法不利于P2P矢量数据的共享和传输。提出一种基于分布式拓扑的P2P矢量地理数据表示模型。该模型结合矢量分片合并的思想,通过扩展WKT(wellknown text)格式来维持矢量数据的拓扑关系。进一步,对该模型的性能进行了数学分析,并基于JTS(Java topology suite)实现了相应的原型系统。理论分析和实验测试结果表明,该模型在选择适当的分片粒度情况下,能使数据传输比率最小化,从而验证了该模型提高数据传输效率和加快矢量数据分片、合并的有效性。
关键词:对等计算技术; 矢量地理数据; 拓扑; 分片; 表示模型
Study of distributed topology based representation model of
P2P vector geography data
WU Jiagao1, HUANG Lin1, ZOU Zhiqiang1, FENG Jiali2, HU Bin3
(1.Institute of Computer Technology, College of Computer, Nanjing University of Posts & Telecommunications, Nanjing 210003, China;
2. School of Geographic & Oceanographic Sciences, Nanjing University, Nanjing 210093, China; 3. Ministry of Education Key Laboratory of Virtual Geographic Environment, Nanjing Normal University, Nanjing 210046, China)
Abstract:Recently, studies of distributed topologic relationship of vector data are few, and vector topological representation is not propitious to sharing and transmission of P2P vector data. This paper proposed a distributed topology based representation model of P2P vector geography data. Combined the model with vector division and union ideas, which extended WKT (wellknown text) format to maintain the topological relationship of vector data. In addition, analyzed performance of the model by mathematical method, and implemented a prototype system of the model based on the JTS (Java topology suite).The theoretical analysis and experimental test results show that the model can minimize ratio of data transmission with appropriate size of tile. Hence, the validity of the model, which can improve the efficiency data transmission and increase the speed of data division and union, is approved.......