The area chart can be a radar plot such as the one shown in this figure:
Each point has a single data value: y. Each point is visualized as a point on an area.
A radar 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. Assigning null for the border or fill effect indicates that the property is unset. Depth is measured relative to the plot area depth (0 = no depth, 1 = depth of plot area).
For more information on the line series object in the API, refer to the RadarAreaSeries class.