Change Blindness in Animated Choropleth Maps: An Empirical Study

Abstract

Animated choropleth maps enable cartographers to visualize time-series data in a way that congruently depicts change over time. However, users have difficulty apprehending information encoded within these displays, and often fail to detect important changes between adjacent scenes. Failures of visual experience, such as change blindness, threaten the effectiveness of dynamic geovisual displays, in which several important changes can occur simultaneously throughout the display. Animated choropleth maps require viewers not only to notice changes but also understand symbolic meanings encoded in rapid transitions between scenes. Graphic interpolation between key frames, also known as "in-betweening" or "tweening", smoothes transitions and lengthens the duration of the transition between scenes in a dynamic sequence. Previous cartographic literature suggests tweening could be a potential solution for change blindness in the cartographic context. This article examines this issue of change blindness in the cartographic context and reports on a human subjects investigation designed to evaluate the influence of cartographic design variables on map readers' change detection abilities. Our results indicate that 1) map readers have difficulty detecting changes in animated choropleth maps, 2) map readers overestimate their own change detection abilities, and 3) tweening influences the legibility of change in animated choropleth maps.

User studies in cartography: opportunities for empirical research on interactive maps and visualizations

“…Hegarty, Montello, Richardson, Ishikawa, & Lovelace, 2006;Miyake, Friedman, Rettinger, Shah, & Hegarty, 2001). We also adopt concepts from psychological studies, for example, how visual attention directs map reading (Carrasco, 2011) and leads to errors in map interpretation (Fish, Goldsberry, & Battersby, 2011), or how individual and group differences in visual and spatial abilities might affect map-use performance (McGuinness, 1994). Furthermore, the cartographic research thrust of geovisual analytics has renewed interest in user studies informed by psychology and the related areas of cognitive science and neuroscience (Andrienko et al, 2007;Thomas et al, 2005).…”

Cartographic Redundancy in Reducing Change Blindness in Detecting Extreme Values in Spatio-Temporal Maps

“…The criticism regarding oversimplification of the animated map used in the studies motivated us to adopt a greater number of enumeration units as it is in [4,19,50]. Animated maps often present the change affecting the phenomenon in a few, or even a dozen, time intervals.…”

“…Each of them served to create a map where color was the main visual stimulus illustrating changes in phenomenon intensity. Previous studies had made use of greyscale color scale [4,19,50]. In our study, we used a color scale from green to red.…”

“…The participants had secondary education and were students of various non-geographic departments. The authors aimed at public users with Internet access, aged 18-24, since other similar studies had focused on such subjects [4,63]. Asked about their frequency of Internet use, they all claimed to use it on an everyday basis.…”

“…As aptly noticed by [1], the problem with animated map perception is not caused by the technology itself, but rather by the limited perceptual capabilities of the user. Many researchers are of the opinion that the problem in question stems from the dynamic nature of such a kind of presentation [2,3], which requires the user not only to perceive the changes occurring on the map, but also to estimate their volume and the moment when they occurred [4]. However, technologies have dramatically changed and D3.js and various map APIs allow us to develop much better maps nowadays with different timeline design options [5,6].…”