PSYCHOPHYSICS IN MAP PERCEPTION
The choice of display parameters for digital maps (e.g., the scale used) depends on the impression the map will generate in the eyes of the viewer. One relevant property of the map is the information load it generates, expressed as the map's perceived density. The number of displayed objects does not solely determine the map density. In an experiment 54 participants evaluated the apparent density of maps showing different terrains at different scales. A model with four properties predicted the apparent density of a map well (R2=0.856). When applying log transforms on two of the variables (number of roads and number of junctions), predictions with these two variables alone were even better (R2=0.903). The study demonstrates the value of applying psychophysical modeling to evaluation of geographic displays and its use in the design of digital map systems.