Architectures for Geospatial Web Services: Issues and Implementations
Çetin CÖMERT and Halil AKINCI-KTU, GEODESY AND PHOTOGRAMMETRY DEPARTMENT
Interoperability can be defined as the ability by which different applications can talk to and cooperate with each other. Although the issue of interoperability for geospatial data processing has been around for almost ten years, the traditional models of interoperability have been criticized being either complex or proprietary. Since the emergence of Web Services has opened up new horizons for Geospatial data processing and interoperability, there has been a tremendous amount of work in geospatial communities to adopt this technology. However, there exist differences in the implementation architectures of the bodies which set the standards for Web services. These bodies are World Wide Web Consortium (W3C) for non spatial or general purpose web services and Open Geospatial Consortium (OGC) for geospatial web services.
The current OGC web services have not been implemented with the W3C Web Services standards such as Web Services Description language (WSDL), Simple Objects Access Protocol (SOAP), and Universal Description, Discovery, and Integration (UDDI). Only recently, there have been efforts to examine the feasibility of implementing OGC web services using W3C Web Services. On the other hand, most of the geospatial data interoperability solutions have been following the OGC way. This fact and the incompatibility between the OGC and W3C Web services architectures make the job difficult when one wants to implement geospatial web services.
In our ongoing work where we want to implement Spatial Data Infrastructures with web services we have been working on addressing these issues. We will summarize our work in this paper with use cases. One of the use cases is our e-municipality project where we have designed and implemented a number of Web Services using W3C standards. Scalable Vector Graphics (SVG) and Document Object Model (DOM) were other components used for the client side functionality.