A cooperated P2P GIS for loose coupled governmental application

摘要

Current governmental applications are of large scale and always compute-intensive and data-intensive, and we focus on introducing P2P computing to facilitate loose coupled governmental applications in this paper. As GIS data is always deposited in locationally distributed nodes, which are probably administrated under spatial databases, the global range is divided into regions to eliminate complicated consistency maintenance and unnecessary message exchanging, and hierarchical spatial indexes are designed for efficient locating spatial resources and low control cost. When executing, a user submitted global spatial query are firstly parsed to sequential subtasks refer to distributed spatial index, and then dynamically passed to appropriate nodes and cooperatively accomplished. Nodes intercommunicate by cooperating messages, which are sent directly to the destination. Besides collaboration process of sequential execution, a dynamic alternative participant approach for failure handling of the sequential execution is provided, which saves the expensive rollback or abort. And this paper also designed and implemented a p2p based loose governmental application prototype, in which nodes intercommunicate via p2p network sub layer, also a user interface is implemented to manage the request from user and eventually reply a result.