Zhong-Ren Peng, Ph.D.
Professor and Director
Center for Advanced Spatial Information Research
School of Architecture and Urban Planning
University of Wisconsin-Milwaukee
PO Box 413
Milwaukee, WI 53201-0413 Email: [email protected]
Chuanrong Zhang, Ph.D.
Department of Geography and Geology
University of Wisconsin-Whitewater
800 Main St Whitewater WI, 53190
Email: [email protected]
A new trend in the development of Internet GIS is the development of Geospatial Semantic Web using Service-Oriented Architecture. This paper introduces the basic concepts of Services-Oriented Architecture and Geospatial Semantic Web, as well as an open standard- based framework of Geospatial Semantic Web based on Services-Oriented Architecture.
In the interoperable Internet GIS environment, the most important issues include how to find who are providing what data and what services, how to access them, and how to integrate geospatial services and data from different services providers. Different data and service providers typically use their own proprietary GIS programs, data models and structures. Since more geospatial data and services need to be embedded in many business operations, such as supply chain management, product tracking and market management, the challenge is how to allow these standard business processes to find and interoperate with currently disparate heterogeneous geospatial systems. Although Internet GIS programs have greatly increased the accessibility of GIS data and tools over the Internet. Those Internet GIS programs have an important limitation, that is, the data and services they provide are not searchable and not interoperable. For example, a geocoding service provided by company A may not interoperate with routing services provided by company B. Each of the commercial Internet GIS programs has its own software design architecture and depends on specific database structures and formats. The mapping and geoprocessing resources distributed over the web by these Internet GIS programs cannot be shared and interoperated. Thus although the current popular commercial Internet GIS products are making progress in performance improvement and ease of use, they have not yet made dramatic or revolutionary changes in sharing geospatial information data and services. A challenging task for the development of Internet GIS is to enable interoperability among heterogeneous systems and geospatial data.
To enable interoperability among heterogeneous systems, there are several technologies, architecture models and service specifications that have been or are being developed. The most important ones include Web Services, Service-Oritented Architecture and Geospatial Semantic Web. This paper makes a brief introduction to each of these technologies and concepts. It will also present a framework to integrate them together in a cohesive manner.
2. Web Services and Web Service Specifications
Web services are commonly used in the IT environment to allow users mix and match different software to support their ever-changing business requirements in a loosely coupled components environment within standards-based integration platforms. The GIS communities have begun using GIS web services for data sharing and web publishing. Figure 1 illustrates examples of sharing different applications and heterogeneous spatial data through web services. However, to fully support service interoperability, standards and specifications should be developed and followed.