Message Exchanges for Web Service-based Mapping Services

The Open Geospatial Consortium (OGC) [1] defines a number of standards, both for data models and for online services, that has been widely adopted in the Geographical Information System (GIS) community. This has lead to a number of software development efforts, online data archives, and application communities. The emergence of Web Service technique overcomes the shortcoming of traditional Distributed Object technique and provides the interoperable capability of cross-platform and cross-language in distributed net environment. GIS services will be implemented more extensively by using Web Service approach. A spatial data infrastructure lets many GIS vendors share data stores and applications in a distributed environment. GIS basically involves the integration of data and services from multiple sources from different vendors. The Web services architecture establishes a standard interconnection rules between services and information clients that nicely support the dynamic integration of data, which is the key to creating a spatial data infrastructure. By introducing Web Services, distributed GIS services from different vendors can be dynamically integrated into the GIS applications using the interoperable standard communication protocols of the Web Services. To be able to benefit from the Web Services in the GIS applications, all the service providers should provide their services as Web Services. General acceptance from the vendors increases the interoperability and enhances the GIS applications. We find that the OGC standards are very compatible with Web Services standards, although they are not technically implemented this way. To be able to benefit from Web Services technologies we have built a common architecture to convert any OGC GIS services to Web Services and applied this to our current WMS project.