Playing with Time - Continuous Temporal Mapping Strategies for Interactive Environments

The growing acceptance of GIS technology has had far- reaching effects on many fields of research. The recent developments in the area of dynamic and temporal GIS open new possibilities within the realm of historical research where temporal relationship analysis is as important as spatial relationship analysis. While topological structures have had wide use in spatial GIS and have been the subject of most temporal GIS endeavours, the different demands of many of these temporally- oriented analytic processes questions the choice of the topological direction. In the fall of 1992 the Montreal Research Group (MRG) of the Canadian Centre for Architecture mounted an exhibition dealing with the development of the built environment in 18th- century Montreal. To aid in presenting the interpretive messages of their data, the MRG worked with the Centre for Landscape Research (CLR) to incorporate the interactive capabilities of the CLR's PolyTRIM research software with the MRG's data base to produce a research tool as well as a public- access interactive display. The interactive capabilities stemming from a real-time object- oriented structure provided an excellent environment for both researchers and the public to investigate the nature of temporal changes in such aspects as landuse, ethnicity, and fortifications of the 18th century city. This paper describes the need for interactive real- time GIS in such temporal analysis projects and the underlying need for object-oriented vs. topologically structured data access strategies to support them