[matplotlib-devel] Completely wrong tick formatting

[Pål G. E. <pa...@gm...>]

Hi

I'm having some problems with the formatter of ticks in a polar plot.
Below is a minimum example
The first figure is correct, the second has wrong ticks.

This has be tested both on 1.2.0 and the latest from git (1.4.x, commit
64cc3416396ffb2811af80fc810ed63572df71d9 )

Does anyone know whys this happens?
Is it a bug in MaxNLocator

Kind regards

Pål

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#!/usr/bin/env python

import numpy as np
import matplotlib.pyplot as plt
from matplotlib.ticker import MaxNLocator

# Data
M=np.sin(np.meshgrid(np.arange(30),np.arange(30)))
M=np.squeeze(M[0,:,:])
Radius=np.arange(30)
Theta=np.arange(30)

# Plotting the correct figure
print('Correct ticks')
fig=plt.figure()
ax1 = fig.add_axes([0,0,0.8,1],projection='polar')
c = ax1.pcolormesh(Theta, Radius, M)
ax1.set_frame_on(False)
plt.xticks([])
plt.yticks([])
ax2=fig.add_axes([0.9,0.1,0.05,0.7])
cb=fig.colorbar(c,cax=ax2)
plt.show()

# Doing the same plot
print('Wrong ticks by using formatter')
fig=plt.figure()
ax1 = fig.add_axes([0,0,0.8,1],projection='polar')
c = ax1.pcolormesh(Theta, Radius, M)
ax1.set_frame_on(False)
plt.xticks([])
plt.yticks([])
ax2=fig.add_axes([0.9,0.1,0.05,0.7])
cb=fig.colorbar(c,cax=ax2)

# except now setting a limit to the number of ticks using a formatter
# which results in wrong ticks
cb.ax.yaxis.set_major_locator(MaxNLocator(3))
plt.show()
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