User-centered Design and Evaluation of a Geovisualization Application Leveraging Aggregated QS Data

Abstract

Individual movement traces recorded by users of activity tracking applications such as Strava provide opportunities that extend beyond delivering personal value or insight to the individual who engages in these “quantified-self” (QS) activities. The large volumes of data generated by these individuals, when aggregated and anonymized, can be used by city planners, Departments of Transportation, advocacy groups, and researchers to help make cities safer and more efficient. This opportunity, however, is constrained by the technical skills and resources available to those tasked with assessing bicycling behavior in urban centers. This paper aims to address the question of how to design cartographic interfaces to serve as mediated platforms for making large amounts of individual bicycling data more accessible, usable, and actionable. Principles of cartographic representation, geovisual analytics techniques, and best practices in user interface/experience design are employed to arrive at an effective visualization tool for a broad urban planning audience. We use scenario-based design methods to encapsulate knowledge of map use practice gleaned from the development process, and conduct a post-implementation two-part user study with seven domain experts to further assess the usability and utility of the interactive mapping tool.

Heat Maps: Perfect Maps for Quick Reading? Comparing Usability of Heat Maps with Different Levels of Generalization

“…Tasks used in the reported study included data retrieval or number estimation. Thus, the very low overall correctness rate obtained in the study (20%) confirmed the observations of Netek et al [4] and Nelson and MacEachren [38] about heat maps not being suitable for reading accurate values from maps. Yet, while locating the "hot spots" in T1 compare, or T3 sort, participants did not obtain better results, although heat maps are recommended for such visual analyses [4].…”

“…Thus, we cannot accept Hypothesis 3, stating that heat map users perceive less generalized maps as easier. Perhaps participants from the reported study recognized less generalized heat maps as "visually noisy", similar to those who took part in the study by Nelson and MacEachren [38]. It might also be possible that the results would have been different had the study material been interactive, as in the studies by Roth et al [41,42] and Nelson and MacEachren [38].…”

“…Linear data could also be used to create heat maps. Nelson and MacEachren [38] studied Metro DataView-an interactive map that depicts data on bike traffic for urban planning purposes-using a raster-to-vector heat map. The authors presented the process of tool development, using scenario-based design techniques.…”