Spatial Applications Integrating Infrastructure Under Web Services

Some details of the design of PAI (Peking spatial Applications Integrating Infrastructure) based on mainstream information technologies such as XML, Web Service, ontology and metadata are presented. Many utilities are using PAI to integrate a variety of spatial databases, systems and business processes. PAI core consists of integrated bus, adapter services, metadata database, PAI mediator and PAI Toolkit. PAI Toolkit is composed of a series of API and Web services. Integrating bus is a group of domain-oriented encoding standards and communication protocols; Adapter service encapsulations are recommended as a good solution to integrate existing applications or systems into PAI; Metadata database is the key unit of PAI, which manages all data and services and shields heterogeneity and distribution of spatial data and spatial services; PAI mediator is positioned to manage metadata and update spatial data online; The terms used in metadata are defined in ontology description language OWL; All data and protocols are encoded in XML; One web service can operate other web services using SOAP protocol. At last, implement details of PAI are discussed, and also a case study of LBS service based on PAI is introduced.