Discussion Paper No. 72R PERCEPTION OF SPATIAL DISPERSION IN THE DISTRIBUTION OF POINT OBJECTS

The present paper analyzed the perception of spatial dispersion in the distribution of point objects. Spatial dispersion is one of the major concepts communicated by dot maps. To promote efficient communication of this concept, two experiments were conducted for investigating the relationship between the perception of spatial dispersion and the following map characteristics: spatial arrangement of points, number of points, symbol size, and map scale. Regression models were then built on the basis of the experiment results to describe the relationship quantitatively. The obtained models enable map authors to predict the degree of spatial dispersion perceived by map readers. From the models and the results of a computer-assisted simulation, the following conclusions were obtained: 1) map scale greatly affects the perception of spatial dispersion, 2) spatial arrangement of points and number of points are also influential, 3) the size of point symbols do not significantly affect the perception of spatial dispersion.