A uniform approach for multi-version web coverage service retrieve based on dynamic schema matching

The Web Coverage Service(WCS) is an important part of geospatial data interoperability. The Web Coverage Service supports electronic retrieval of geospatial data as “coverages” - that is, digital geospatial information representing space-varying phenomena. Open Geospatial Consortium (OGC) has already developed standard implementation specifications for web coverage service, and for those web coverage services with different versions, such as WCS1.1, WCS1.0. OGC also define different schemas. Web coverage service with different versions have different schema files and different version service support different data formats, all these result in problems for interoperablility among web coverage service with different versions. Such as user only request some version WCS service specified by the WCS server,when WCS server find that the request service version is not supported by it may cease communicating with user. In order to access multi-version web coverage service in a uniform interface, the paper design a uniform approch for multi-verson WCS service retrieve middleware to match different version schemas dynamically and automatically transform the XML result document into a form that meet the requirement of user request. At end the whole system's schema matching quality and information retrival efficience have been tested successfully in GeoServer WCS services, the tested results show the feasibility of the designed approach.