A component perspective on geographic information services

This paper explores the notions of geographic information services in the context of component technology. It suggests that componentization gives rise to an alternative view on GIS as geographic information services. The change from monolithic systems to component-oriented systems requires examination of the service structure of GIS. The paper presents a general discussion on the notions of component and services. A combination of existing reference models of information services and an empirical model of software evolution is used to identify geographic information services. Application services, functional services, and common services are considered to the main groups of information services in the component architecture. The discussion focuses on the functional services and common services within the domain of geographic information processing. Eight groups of such services are identified. They represent a reorganization of geographic information services in light of recent advances in component technology. The service structure is substantially different from the functional components of traditional GIS. The requirement for inter-operation adds several groups of common services, including data access, catalog, transformation, and registry. Developing the components for geographic information services presents both technical and theoretical challenges. In the theoretical domain, the problem of representation is crucial for achieving high levels of interoperability. The concepts are further elaborated through an example on how component technology makes it easy to use advanced geographic techniques through a distributed spatial statistical modeling service.