The area chart can be a polar plot such as the one shown in the following figure:
Each point has two data values: x (angle) and y (radius). Each point is visualized as a point on an area.
A polar area series can be assigned a border, fill effect, and a depth for the area. Each point can be assigned a border and a fill effect for the area. You can also specify whether the area is closed. Assigning null for a border or fill effect indicates that the property is unset. Depth is measured relative to the plot area depth (0 = no depth, 1 = full depth of plot area).
For more information on the area series object in the API, refer to the PolarAreaSeries class.