[Matplotlib-users] synchronization of ticks position in twinx plots

[Pierre H. <pie...@cr...>]

Hello,

In relation to the recent thread on pareto chart, I have a question with
regards to the synchronization of ticks location when using twinx plots.
This question may have been adressed in the past, but my Google search
on this topic was unfruitful. Sorry if this question was already answered.

Basically, when using twinx two plot two different data sets, the scale
of the data, in the general case, is to be different (thus the need for
twinx). However, adding a grid to such a twinx plot leads to a very
irregular placement because the ticks positions are not "synchronized".
(I pasted a quick example to illustrate the tick placement issue at the
end of this message)

Ideally, I would like that both axis share a common placement for the
ticks. Is there a way to do that ?

I guess this would require that the two ticks Locators share "some
algorithm" so that they would "agree" on the placement instead of
working separetely. Other option may be that one Locator could work as a
slave of the other one. (I'm just trying to draw a rough picture)

Best,
Pierre

quick example to illustrate the tick placement issue :

import matplotlib.pyplot as plt

ax1 = plt.subplot(111)
ax1.plot([1,2,3], 'bo-')
ax1.grid(True)

ax2 = plt.twinx(ax1)
ax2.plot([11,12], 'rs-')
ax2.grid(True)

ax1.set_xlim(-0.5,2.5)

plt.show()