Visualizing changes in a dynamic Voronoi data structure via time travel

In recent years there has been rapidly growing interest by the GIS community in new visualization methods for cartographic data. The visualization of map changes is important for several reasons: spatio-temporal analysis, process modelling, and animated maps. It is nowwidely recognized that currentGIS software has no ability tomaintain incremental change of spatiotemporal data, and therefore visualization of such data is limited to series of ‘snapshots’ of cartographic data (see [Peque94a]). The growing amount of research on spatio-temporal databases shows that today’s world of spatial data handling requires a dynamic and interactive environment for map visualization. In this paper we will present a conceptual approach for representing cartographic data changing in time and space. The approach emphasizes several research efforts: on the Voronoi spatial data structure, the reversibility of its map construction commands, and their applicability to map visualization and map animation.