The Geographic Structure Query Language Based on the Peer to Peer and Cooperating Computing Hybrid Discovering Model

The management of the magnanimous spatial data needs the distributed cooperative GIS platform. This paper proposed the Peer To Peer and Cooperating Computing Hybrid Discovering Model of Distributed Geospatial Information. Based on the (Spatial Resource Discovery Agent (SRDA) and ordinary neighbor node, Combined with Spatial data model of MAPGIS7.0, this article brings up the geographic structure query language in P2P network (P2PGSQL), and has designed the interpreter of P2PGSQL. In the Peer To Peer and Cooperating Computing Hybrid Discovering Model, this paper has designed the algorithms that construct the distributed hash table and decrease the delay. By discovering and performing the potential swaps that are beneficial to the match between overlay and physical network, it can reduce the average latency and improve the performance of the system. Based on the P2P Cooperating Computing Hybrid Discovering Model, this article has given the method of the P2PGSQL in grid environment and built the mapping model of the global spatial query sentence to the local query sentence. With constituting a global spatial data resource catalog to record the distributing information of all spatial database on each node, P2PGSQL has backed up effective expression of spatial database management mission in grid environment. Hence, P2PGSQL can sustain the query of distribute spatial data in grid environment. This article has extended the grid spatial relation operation (Intersection, Union, Difference) and synthesized operation (Length, Buffer, intersecting region) and so on. The P2PGSQL can reduce the quantity of spatial data transmitting among nodes and enhance the capacity of parallel operation. At the same time, P2PGSQL can also sustain multi-spatial data model by the extension of structure data on the data type. At the end, an experimental instance of P2PGSQL has been carried out based on mapgis7.0 platform.