The Impact of Bivariate Symbol Design on Task Performance in a Map Setting

Abstract

Abstract:Research conducted on the theory of selective attention suggests that varying the graphic combinations used when designing bivariate symbols affects the functionality of the symbol. Some graphic combinations appear to facilitate the ability to visualize correlation between the data sets represented by the symbol; others appear to be more effective at representing the data sets individually, some even at the expense of extracting correlational information. The purpose of the research described here was to test the strength of these findings in a map use context. Several bivariate symbol designs were tested using map use tasks designed to test participants' abilities to extract either correlational or individual information. Participant reaction times provided an assessment of the types and levels of interactions that occurred with each symbol set, Results corroborate previous research in both cartography and psychology, with several symbol designs falling into each of three interactional categories: separable, integral, and configural. By confirming and expanding previous research, this study provides further evidence of the strength of selective attention theory in aiding the design of bivariate thematic maps.

Testing the Effects of Thematic Uncertainty on Spatial Decision-making

“…It would be interesting, for example, to combine suitability and certainty into a multi-dimensional symbol. This would enable direct consideration of some of the ideas concerning multi-dimensional graphic symbols discussed by Ashby and Gott (1988) and Nelson (2000a;2000b). Alternatively, some of the recent dynamic methods for displaying uncertainty information, such as probability distribution functions (Pebesma et al 2006), might be tested to see if the same biases are exhibited when more detailed information is available.…”

A Transition in Improving Maps: The ColorBrewer Example

“…A basic principle for categorizing selections of multivariate symbols might be the notion of separable versus integral visual variables (Nelson 2000). Representation of proportions of a whole versus a comparison of amounts also offers another basic categorization of point symbols (Brewer and Campbell 1998).…”

Deconstructing Galbraith: A Geostatistical Analysis of Cartographic Intent

“…As long as the other aspects of cartographic design are fairly standard, unconventional symbols can be quite effective (Guelke, 1979), especially then they are more visually stimulating (Lai and Yeh, 2004;Nelson, 2000;Shortridge, 1982). Further assisting the reader at comprehension is the relatively large, colourful nature of Galbraith's mimetic symbols, both of which qualities encourage cartographic legibility (Castner, 1997;Morrison and Forrest, 1995;Shurtleff and Geiselman, 1986).…”