Converting a spline chart to a polar/radar chart

Polar (or radar) charts are generally used for spotting data trends. They have few differences to line and column type charts. Even though it may look like a pie chart, it has nothing in common with one. In fact, a polar chart is a round representation of the conventional two-dimensional charts. To visualize it another way, it is a folded line or a column chart placed in a circular way with both ends of x axis meeting together. The following screenshot illustrates the structure of a polar chart:

As there are very little differences in principle, the same also applies to the Highcharts configuration. Let's use our very first example browser's usage chart in Chapter 1, Web Charts, and turn it into a radar chart. Recalling the browser's line chart, we have the following:

To turn the line chart into a polar chart, we only need to set the chart.polar option to true which transforms the orthogonal x and y coordinates into a polar coordinate...