Comparing Color and Leader Line Highlighting Strategies in Coordinated View Geovisualizations

In most coordinated view geovisualization tools, a transient visual effect is used to highlight observations across views when brushed with a mouse or other input device. Most current geovisualization and information visualization systems use colored outlines or fills to highlight observations, but there remain a wide range of alternative visual strategies that can also be implemented and compared to color highlighting to evaluate user performance. This paper describes the results of an experiment designed to compare user performance with two highlighting methods; color and leader lines. Our study methodology uses eye-tracking to capture participant eye fixations while they answer questions that require attention to highlighted observations in multiple views. Our results show that participants extract information as efficiently from coordinated view displays that use leader line highlighting to link information as they do from those that use a specific color to highlight items. We also found no significant differences when changing the color of the highlighting effect from red to black. We conclude that leader lines show significant potential for use as an alternative highlighting method in coordinated multiple view visualizations, allowing color to be reserved for representing thematic attributes of data.