Using Polar Charts

In this chapter, you will learn how to use polar charts to represent in a circular way both angle values and non-angle values.

By default, a polar chart represents data expressed in polar coordinates (θ, ρ) in a circular way. The abscissa values θ are expressed in degrees and are mapped along a circular scale graduated in degrees by default. Therefore, you will use a polar chart to represent data whose abscissa values are expressed in degrees. However, a polar chart can also be used to get a circular representation of any data you want, even if the abscissa values are not expressed in degrees. To do this, you can do one of the following:

Apply a transformation to the abscissa scale to convert the abscissa values into degrees. In this case, the abscissa scale will be graduated in degrees, no matter what the initial data may be.

Indicate to the projector that the values to be projected are not expressed in degrees and then set a starting angle and a range to tell the projector how the abscissa values are mapped along the abscissa scale. In this case, the abscissa scale will bear the original abscissa values instead of being graduated in degrees.

In this chapter, you will see two examples that show how to represent data that are not expressed in degrees on a polar chart.