Colorbar offsetText (scientific base multiplier) move from top to bottom of colorbar

Question

I\'m losing my wits here with this \'simple\' problem:

In the colorbar (illustrated in picture) in matplotlib I need to move offsetText (base multiplier) from top of

Answer 1

Hmmm... Apparently, it's not possible to move colorbar's scientific base multiplier up or down, just slightly left or right.

Workaround would be to hide it and just add (same) custom text that would be positioned at the bottom (in my case):

    cb.ax.yaxis.get_offset_text().set_visible(False)
    cb.ax.text(0.5, -0.1, '1e4', va='bottom', ha='center', size=6)

If someone has more elegant solution, I would be happy to see it!

Answer 2

It's in general not possible to change the position of the offsetText label. This would still be an open issue.

A solution can therefor be to overwrite the yaxis' _update_offset_text_position method to position the offsetText on the bottom of the yaxis.

import matplotlib.pyplot as plt
import types

def bottom_offset(self, bboxes, bboxes2):
    bottom = self.axes.bbox.ymin
    self.offsetText.set(va="top", ha="left")
    self.offsetText.set_position(
            (0, bottom - self.OFFSETTEXTPAD * self.figure.dpi / 72.0))

fig, ax = plt.subplots()
im = ax.imshow([[1e5,2e5],[0.1e5,1e5]])
cb = plt.colorbar(im)
cb.formatter.set_scientific(True)
cb.formatter.set_powerlimits((0,0))

def register_bottom_offset(axis, func):
    axis._update_offset_text_position = types.MethodType(func, axis)
register_bottom_offset(cb.ax.yaxis, bottom_offset)

cb.update_ticks()

plt.show()

If the colorbar is positioned on the left side of the plot the following might look better:

self.offsetText.set(va="top", ha="right")
self.offsetText.set_position(
            (1, bottom - self.OFFSETTEXTPAD * self.figure.dpi / 72.0))