A distributed geographic information system on the Common Object Request Broker Architecture (CORBA)

摘要

A distributed geographic information system (distributed GIS) has strengths in system reliability, efficiency, resource sharing, and flexibility for incremental system growth. However, developing a distributed GIS is a challenging task. The major challenges are with generating efficient system-wide query strategies, synchronizing operations executed at different sites, handling heterogeneity, managing transactions, and so on. In this paper, an experimental system is reported. This work is aimed at addressing the fundamental issues in building a distributed GIS. This system is designed and implemented based on the Common Object Request Broker Architecture (CORBA), and the Open GeoData Interoperability Specification (OGIS). First, the use of the CORBA model for a distributed GIS is discussed. The major system components are described, including the local GISs, the object request broker (ORB), and the service objects. Subsequently, a query optimization algorithm is presented. Then system synchronization, heterogeneity handling and transaction management are described. Some important implementation issues and the results of system tests are presented. Finally lessons learned from building the experimental system are summarized.