WIP DataArray.plot() can now plot errorbars with kwargs xerr, yerr

[dcherian]

• Tests added (for all bug fixes or enhancements)
• Tests passed (for all non-documentation changes)
• Fully documented, including whats-new.rst for all changes and api.rst for new API (remove if this change should not be visible to users, e.g., if it is an internal clean-up, or if this is part of a larger project that will be documented later)

Added support for errorbar plotting. This works by providing the kwargs xerr and/or yerr to plot() or plot.line(). It will only work for 1D data.

Errorbars for plots that usehue argument require that we loop and plot each line individually. I'm happy to add this is you think it's a good idea.

Example from docs:
air.isel(time=10, lon=10).plot.line(y='lat', xerr=3, yerr=1.5, ecolor='r')

[shoyer]

Very cool!

Errorbars for plots that usehue argument require that we loop and plot each line individually. I'm happy to add this is you think it's a good idea.

I'm pretty sure that under the covers matplotlib uses a loop when plt.plot results in multiple lines. So this seems pretty reasonable to me.

[jhamman]

Looks good to me. Just a minor docstring suggestion.

[jhamman]

Can we expand this description?

[marccheneau]

Hi there. I have read this thread with a great interest as I was wondering whether it was possible to plot data from a Dataset with errorbars. Yet it seems that the changes discussed here were not merged in the end. At least I can't find the corresponding piece of code in the latest version of xarray/plot/plot.py.
What is the current status of this feature?

[dcherian]

This never went in because I never finished it :)

One bit of weirdness is that the return types are different for plt.plot and plt.errorbar so the return type for xarray.plot will change when xerr or yerr is specified. I don't know if we should care too much.

Feel free to take over

[marccheneau]

I will have a look at it, starting with your initial commit. Regarding the change of return type, I won't be able to judge whether this can cause trouble or not.