1 dimension (time:daily) + 1 metric
Used to compare the day-by-day evolution of a metric on a calendar view. We can then detect patterns on two different temporal axes : (a) at a week-view, reading the calendar top to bottom to see if a day of the week stands out for over/under performance, and (b) at a year-view, reading the calendar left to right to compare performance between periods.
A simple example
Let's say you want to understand when people are coming to your website.
Try it with your own data on the Visualization Playground
Let's analyze a bit
Reading the three tiles we directly see that the best day fell in the best week of the best month (April).
Reading the calendar from left to right, we can spot out that the period around April 2nd had a higher amount of visits out of both months. Total visits slightly decreased until December.
A top-to-bottom calendar view makes it apparent that visitors only really access your website between Monday and Friday.
Is it normal?
What happened on April the 2nd?