A heatmap (or heat-map) is a graphical representation of data that uses a system of color coding to represent different values. Heatmaps are used in various forms of analytics but are most commonly used to show user behavior on web pages and mobile apps.
Using color codes, a heatmap visually represents how a user interacts with a webpage. The color scale ranges from blue (least interaction) to red (most interaction).
Heatmaps allow you to assess which website elements users click on and scroll through or which they ignore.
Read more on heatmaps in Piwik PRO help center: Piwik PRO site inspector for Chrome
Here is an example of a heatmap: