Visualization of spatio-temporal information in the Internet

Maps are traditional means of presentation and tools for analysis of spatial information. The power of maps can be also put into service in analysis of spatio-temporal data, i.e. data about phenomena that change with time. Exploration of such data requires highly interactive and dynamic maps. We implement such a kind of mapping in a collection of Java applets designed for various types of spatially referenced time series data: occurrences of events, movement of objects in space, and statistical data referring to parts of territory. As a theoretical background, we develop a classification of analytical tasks depending on what aspect of a spatial phenomenon varies with the time (existence, spatial location, size and shape, or thematic properties) and what kind of view is required, with respect to time (instant, interval, or overall). On the basis of this classification, we select appropriate presentation techniques and devise interactive map manipulation tools supporting various kinds of tasks.