Understanding the relationship between chart, pie, and series

Pie charts are simple to plot: they have no axes to configure and all they need is data with categories. Generally, the term pie chart refers to a chart with a single pie series. In Highcharts, a chart can handle multiple pie series. In this case, a chart can display more than one pie: each pie is associated with a series of data. Instead of showing multiple pies, Highcharts can display a donut chart that is basically a pie chart with multiple concentric rings lying on top of each other. Each concentric ring is a pie series, similar to a stacked pie chart. We will first learn how to plot a chart with a single pie, and then later on in the chapter we will explore plotting with multiple pie series in separate pies and a donut chart.