A Standard Based Spatial Information Service Model for Adaptive Services Chaining

摘要

Spatial information service is a fundamental element for sharing and interoperating spatial information. Several reference specifications have been constituted by ISO and Open GIS Consortium (OGC) to provide standard interfaces of different services. For the purpose of complex task, chains distributed atom service together is a possible solution. How to link spatial information services quickly, efficiently and adaptively is quite important. This paper presents a model for chaining spatial services by employing Web Processing Service (WPS) and Business Process Execution Language for Web Services (BPEL4WS) under the service-oriented architecture (SOA) and OGC standard. Workflow control and SQL Server based register center were employed for chaining spatial services which have been performed functionality decomposition and packed by using extended WPS. For adaptive services chaining in this model, atom service was packed as spatial agent (SA); and statues of single service was monitored. Negotiation strategy was brought in to balance statue (such as servicepsilas prerequisite, time consuming etc.) of multi-SA (exception handling) in services chain for choosing best service to be linked by standard interfaces.