GeezerVison

Also: this does not (yet) include changes to the docstrings, i.e. the following will need to change:

"""

Parameters
----------
X : array-like or PIL image
    The image data. Supported array shapes are:

    - (M, N): an image with scalar data. The values are mapped to
      colors using normalization and a colormap. See parameters *norm*,
      *cmap*, *vmin*, *vmax*.
    - (M, N, 3): an image with RGB values (0-1 float or 0-255 int).
    - (M, N, 4): an image with RGBA values (0-1 float or 0-255 int),
      i.e. including transparency.

    The first two dimensions (M, N) define the rows and columns of
    the image.

    Out-of-range RGB(A) values are clipped.
"""

to include a line like

"""
etc.
    - (K, M, N): multiple images with scalar data when combined with a
    multivariate or bivariate colormap using a MultiNorm.
"""

I updated the docstrings, so now this PR should be ready for review.

There is an error with the docs on circleci, but I haven't found a link between the error and the changes made in this PR, so I believe it to be unrelated.

@story645
Thank you for the feedback :)
I believe I have addressed all the comments now (I'll mark them as resolved in the coming days).

also: this will need a squash-merge

If you've got the bandwidth, @greglucas can you give this a look (skim) since you've been working on colormapping?

@story645 @tacaswell would you two be willing to finish your review of this?
Or perhaps @ksunden?

EDIT: my apologies @story645 I didn't see you had just assigned this when I wrote my comment :)

@anntzer asked if the more cleanup/refactor/not directly necessary for implementation parts of this PR could be spun off into a different set and if this PR could get rebased to clean up the commit history.

(Just to give an example, I'm currently splitting off #29807 into a bunch of smaller preparatory PRs: #29817, #29828, #29838, #29843, #29829.)

@anntzer I'll see what I can do.
I thinking of splitting it as:

1. MultiNorm class
2a. Add support for multivariate pcolor and pcolormesh + tests 
2b. Add support for multivariate imshow + tests

I'll also see if there are some misc changes that can be a separate PR between 1 and 2.
In any case, 1. will have to be merged before 2a and b. Would you like me to make all the branches at once, or does it make more sense to make the PR for 2a and b once 1. is merged?

I guess it doesn't really matter, because we know the end result thanks to this PR anyways.
(I won't be able to review anything before next week, in any case.)

@anntzer @story645 I opened PRs:
#29876 → The MultiNorm class
#29877 → Other changes needed to expose the functionality.

Hopefully this is easier to review :)

@trygvrad moved this to Superseded in Bivariate and Multivariate Colormapping on Jul 3

Should this be closed if it's superseded?

@trygvrad moved this to Superseded in Bivariate and Multivariate Colormapping on Jul 3

Should this be closed if it's superseded?

Yes :)