1 dimension + 1 metric
The bars allow the comparison of a large number of different elements within the same dimension, sharing a common metric. Effective for showing a time evolution, that is to say where the dimension is time and each value of the dimension is a date.
A simple example
Let's say you want to visualize your website's visits over time. Here, the dimension is
time:monthly so each bar is a month and the metric is
visits so each bar height is relative to the number of visits for this month.
Try it with your own data on the Visualization Playground
Let's analyze a bit
At a glance we can see that there’s seasonality in our database, with almost regular sinusoidal variation.
At the same time, we can see that 2013 outperformed 2012.
As we take a closer look, we see that our best months in both 2012 and 2013 are February, March and April. Moreover, we can quickly spot that 2013 outperformed with a gap consistent with other months. We can also note that September was consistently positive with significant audience peaks, as compared to appalling performance in August. of both years.
So what does this mean for our business?