JUDGING THE SIMILARITY OF CHOROPLETH MAP IMAGES

An experiment was conducted to determine if people can form mental images of choropleth maps, if they can compare map patterns on those images, and if they make the comparisons in the same way that people make visual comparisons of map patterns. Subjects committed choropleth maps to memory and were given experience in the use of these images to make judgments of pattern similarity. After using imagery in a preliminary comparison task, the subjects were asked to rank the similarity of all possible map pairs. The subjective similarity rankings were compared to objective measures of the map patterns. The findings of this experiment are related to those of an earlier study in which the subjects compared the similarity of the same maps visually. The results indicated that there were no significant differences in the way choropleth map patterns were compared visually or from memory.