Geovisualization

A New Kind of Map Use?

Static maps have been used over the centuries to gain insight into geographic data sets and conduct exploratory spatial analysis. Perhaps the most cited example is John Snow's mapping of cholera cases in Soho, London, where a geographic association between cholera cases and a water pump was visually detected when the locations were mapped. The pattern was apparently used to infer the relationship between the disease and drinking water. The popularization of maps that are designed specifically for exploration is more recent, however. It is associated with a move away from formal to exploratory analytical methods and the use of computers to produce specific, specialized, and often very abstract maps rapidly, in response to particular enquiries. As computers have advanced and forms of interaction and representation have progressed to support exploratory map use, geovisualization and the interest in maps as exploratory interfaces to data have developed.

In the mid-1990s, the International Cartographic Association responded to changes in map use through a commission that identified visualization as the use of interactive maps that were designed for individual experts to support thought processes. This differed from the more traditional use of maps to communicate a known message to a wide audience through static cartography—and much of conventional cartography had focused on methods and techniques to support these aims. A conceptual model of map use, named the “[cartography]3” was produced by Alan MacEachren and other members of the commission to reflect these changes. This [cartography]3 uses three [Page 210]orthogonal axes to represent the goals of map use (from information retrieval to information exploration), the breadth of intended audience (from individual researcher to public), and the degree of flexibility provided by the map (from low/static to highly manipulable). Together, they define a threedimensional space that establishes the differences between maps designed for communication and those suitable for visualization and that draws attention to opportunities for cartography and geovisualization.

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