Choriented Maps: Visualizing SDG Data on Mobile Devices

ABSTRACT Choropleth maps and graduated symbol maps are often used to visualize quantitative geographic data. However, as the number of classes grows, distinguishing between adjacent classes increasingly becomes challenging. To mitigate this issue, this work introduces choriented maps (maps that use colour and orientation as variables to encode geographic information) and choriented mobile maps (an optimization of choriented maps for mobile devices). The maps were evaluated in a graphical perception study with Sustainable Development Goal data of several European countries. Choriented maps and choriented mobile visualizations resulted in comparable, sometimes better effectiveness and confidence scores than choropleth and graduated symbol maps. The two visualizations also performed well regarding efficiency and only performed worse than graduated symbol maps. These results suggest that using colour and orientation as visual variables in combination can improve user performance and their selection of map symbols during the exploration of geographic data in some scenarios.