A comparison of performance using extrinsic and intrinsic bivariate cartographic visualizations with respect to cognitive style in experienced map users

When spatial information is depicted on univariate or multivariate maps, different visualization designs should be considered to fit the designs to suit the target audience and define the map's general purpose and therefore also the map user's expected cognitive processes. Although multivariate maps have attracted research for decades, only several studies have compared the effectiveness of maps that use extrinsic and intrinsic encoding styles, and even fewer have tried to incorporate other map-related factors that could significantly affect the user's performance and clarify the relationship between the selected encoding style's efficiency and the user's cognitive processes. In this paper, we report on an empirical replication study focused on the performance differences of experienced map users solving a task using a map and the possible effect of their cognitive styles on the efficiency of bivariate map encoding styles and the map task type. For the experiment, we recruited 77 spatial planning and geography university students in China considered as experienced map users. The study indicated that extrinsic visualizations outperformed intrinsic visualizations in the main observed variables of correctness and response time but not always significantly. A detailed analysis of the tasks, which involved the use of either one variable or two variables concurrently, confirmed our hypothesis.