If we’re constantly talking about primary axes, there must also be secondary axes. The charts of the types that have been discussed so far in this chapter can be equipped with second value axes and second category axes.
The chart consists of more than one data series.
If a second category axis is to be set up, a second value axis must already exist.
As a result, your chart can have three or even four axes instead of only two, and they can all be labeled. And it gets even a little more complex: as with the primary axis, your chart can also have secondary axes that remain invisible but still influence the design capability of the data series.
There are two main reasons for doing this:
You want to or have to ...