中文摘要：

网格GIS的研究重点在于利用网格技术，基于空间数据库实现空间资源共享。网格环境下，用P2P模型解决副本管理问题，可增强系统的可伸缩性和动态性。在网格GIS中，逻辑层与物理存储层分离，采用水平非交叠分片策略，依照空间区域把逻辑层划分为物理片段层。网格GIS应用系统应用GT4部署和实现，在网格上使用JXTA协议建立虚拟网络覆盖层，实现由门户节点、聚合点和物理存储节点组成的层次型全局副本目录结构。为提高空间数据发布效率，采用三层分布式索引结构，物理片段层和逻辑层分别采用R-tree索引和四叉树索引，通过软状态协议维护副本目录的一致性，并讨论副本目录原型GridSRC的实现和性能评价。

英文摘要：

In grid environments, the mechanism of using P2P model to solve the problem of grid resources organization can im- prove the scalability and dynamics of the system. The horizontal and non--overlapping fragmentation method was used to partition a logical layer into physical fragments according spatial region. GT4 is used to deploy and implement the grid GIS application system,and a virtual P2P overlay network is built through JXTA protocol above the grid system. The paper proposes a mechanism, named GridSRC, which is a JXTA-based hierarchical framework for replica location mechanism. Accordingly three tied distributed index structure was implemented,R-tree index was used in fragment layer and quad-tree index was used in logical layer. Replica catalog consistency was maintained by means of soft state protocol. The distributed storage and redundancies of fragments increase the parallel degree of spatial query and refinement. This mechanism not just improves query speed and load balance, but also makes asynchronous rendering and parallel spatial analyzing possible. Thus the response time on client is shortened remarkably. Finally, the implementation and performance evaluation for the prototype was put forward.