Lets maybe get#21794 in first...

@jklymak oops, sorry - didn't see it when I started this one. Yes of course, will rebase then if necessary.

many of these edits are great, and thanks for catching the spelling errors!

We need to be careful about mission creep in this document. You've suggested adding multiple axises/secondary axis to the figure. One could also add more colorbar, inset axes, etc etc. Maybe instead of full examples, lets just have some text that links to relevant examples for twinx and secondary_ax?

@jklymak

We need to be careful about mission creep in this document.

You're right, but IMHO a second y axis may be used more frequently than say math text or annotations (especially when you are used to Excel where you can send a data series with just one click to a second y axis on the right). I'd love to just refer to some tutorial on secondary, twin and shared and parasite axes (the latter two I left out intentionally), but there is none. So I tried to illustrate the concepts with two minimalistic examples as a short example is easier (at least for me) than describing the functionality in words.

Maybe we can combine the two paragraphs into one and show the examples side by side to make it even more concise (athough subplot are only introduced further down the tutorial, but the color mapped data section also uses subplots). But in the end I'm also happy with just the links to some examples.

Well, lets let others weigh in. My vote would be to trim rather than to add ;-)

There are quite a few twinx examples:https://matplotlib.org/stable/api/_as_gen/matplotlib.axes.Axes.twinx.html and there is a seocndary_axis example:https://matplotlib.org/stable/gallery/subplots_axes_and_figures/secondary_axis.html#sphx-glr-gallery-subplots-axes-and-figures-secondary-axis-py

@jklymak sure, no problem.

Just in case: this is a less space-consuming version by putting the plots side by side:

I'm in favor of taking this extra section. I think twinned and secondary axes are on the same level of importance with annotations (but a bit behind math text) ;)

This is something that is particularly hard to describe to google so having a picture and link is 👍

My vote would be to trim rather than to add ;-)

Is that a case for making an intermediate usage? Where basic is stripped down to how do I make one thing & label it, and intermediate is more of a grab bag of very commonly asked for things?

Please, no more grab bags!

But I'm warming to this section particular if it links out to the other examples. If the subject requires expansion or unification of those examples a new tutorial might make sense.

@jklymak Sorry for being a pain in the neck, but I also changedconstrained_layout=True tolayout='constrained'. This tutorial states "This tutorial covers ... and best practices ...", so I thought it shouldn't show discouraged usage:

No, not a pain - I forgot about that change.