ETUX021: Figure 1.9
A heatmap is a commonly used (and misused) eye tracking data visualization. It represents the values of a variable (for example, gaze duration) as colors, where the amount of “heat” is proportional to the level of the represented variable.
Bojko, Aga. 2013. Eye Tracking the User Experience. New York: Rosenfeld Media. rosenfeldmedia.com/books/eye-tracking-the-ux/