Persistent programming languages are targetted primarily at application systems involving complex data structures and relationships, as typified by Geographical Information Systems (GIS). The many sophisticated GIS products available today were developed before concepts like persistence and object-orientation had been well-established, and there is an urgent need to construct new GIS technology that can benefit from the advances made in these two areas of Computer Science. This will not only alleviate problems in existing GIS systems caused by the impedance mismatch, but can also expand its capabilities by providing for effective spatio-temporal manipulation of geographic data. The popularity, accessibility and characteristics of Java(TM) make it a very attractive vehicle for this. in this paper we propose an architecture for spatio-temporal data access in PJama. We describe our prototype implementation of this architecture along with its application in a marine biology project. Initial results indicate that PJama is a viable implementation platform for spatio-temporal GIS. As our prototype nears completion we begin performance evaluation to substantiate this claim and measure the effectiveness of PJama GIS under large, real-world application loads.
