# RGraph: HTML5 canvas graph library - Bi-polar chart

The Bi-polar chart is also (possibly more commonly) known as an age-frequency chart or a population pyramid. It allows you to very straight forwardly compare two sets of data. For example two years worth of sales figues. Using this type of chart abnormalities will become apparent. Other charts that would also be comparable, include a grouped bar chart, a stacked bar chart, and a multiple line graph.

- Bi-polar chart API documentation