INFLUENCES OF MAP CONTEXT ON CIRCLE PERCEPTION∗

∗This study was supported in part by a Dissertation Fellowship from the University of Kansas. The author would like to express her appreciation to Professor George Jenks under whose direction the research was conducted.

ABSTRACT

The nature of the cartographic environment within which a proportional circle is seen can influence the perceived characteristics of the map symbol. The apparent sizes of circles may be biased by: 1) the effect of size contrast between a target circle and closely adjacent circles; 2) the presence or absence on the map of internal borders; and 3) the size of the target circle itself. Statistical analyses indicate that size contrasts between a given map symbol and other symbols in the immediate area do alter the perceived size of the symbol. Target circles that were viewed within the context of smaller circles appeared to be larger (by an average of thirteen percent) than the same target circles when they were seen among large context circles. The presence of internal map borders tended to reduce the differences in estimates that resulted from size contrast between a target circle and adjacent circles.

Notes

∗This study was supported in part by a Dissertation Fellowship from the University of Kansas. The author would like to express her appreciation to Professor George Jenks under whose direction the research was conducted.