Network-enabling GIS: issues, models and a review

Networking GIS tools and applications vary greatly in both function and architecture. In this paper, we will provide a framework to study the problems of networking GIS. GIS resources consist of geodata and geoprocessing capabilities. From the viewpoint of geodata sharing, it is observed that decoupling geodata and geoprocessing is necessary given the difficulty of integrating autonomous GIS systems, and geodata catalogue service can be an alternative to tightlycoupled multiple GIS systems in certain circumstances. For the data-processing coupled case, we first examine various distributing possibilities of deploying geodata and geoprocessing capability in network environments. Then issues involved the integration of geodata and geoprocessing in different distributed computing architectures are then discussed. For the client-server architecture of distributed GIS, there is the problem of data model mismatch between GIS tools and spatial database based on general-purpose DBMS, which lacks support in fundamental spatial modeling concepts such as a map. The possible result of this data model mismatch is analyzed. For federated architecture, it is argued that most interoperable GIS under research assumes read-only access mode. Some validation of this assumption and its consequences are made in this paper. It is also identified that tools for geodata schema integration and geodata integration are needed, and we will review the status of research in these issues.