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[Bug]: Removing spines in polar plot causes distortion of the plot #30164
Description
Bug summary
I would like to create a polar plot without the grid lines. When using ax.set_xticks([]) (and/or yticks/rticks) the plot appears distorted.
Code for reproduction
import numpy as np
import matplotlib.pyplot as plt
D = np.array([[2,.3],[.3,2.5]])
# creating an ellipse)
lam, vec = np.linalg.eigh(D)
theta = np.linspace(-np.pi,np.pi,1001)
xy = np.stack((lam[0]*np.cos(theta), lam[1]*np.sin(theta)), axis=0)
xy = vec.T@xy
radii = np.sqrt(np.sum(xy**2, axis=0))
thetas = np.arctan2(-xy[1],xy[0])
plt.figure()
# with ticks
ax1 = plt.subplot(121,projection='polar')
ax1.plot(thetas, radii)
# without ticks
ax2 = plt.subplot(122, projection='polar')
ax2.plot(thetas, radii)
ax2.set_yticks([])
ax2.set_xticks([])
plt.show()Actual outcome
Expected outcome
Additional information
No response
Operating system
OS/X and Linux
Matplotlib Version
3.10.0
Matplotlib Backend
module://matplotlib_inline.backend_inline
Python version
3.10
Jupyter version
No response
Installation
None
Activity
anntzer commented on Jun 12, 2025
This is essentially the same issue as the one fixed by #29798, but uses set_yticks instead of set_rticks. I suspect that PolarAxes.set_yticks should get the same treatment (of wrapping into a RadialLocator); indeed, using set_rticks([]) works fine as of HEAD.
timhoffm commented on Jun 13, 2025
Fundamentally, shouldn't we implment everything in set_yticks and make set_rticks only a synonym of that?
anntzer commented on Jun 13, 2025
Yes, I would think so.
timhoffm commented on Jun 13, 2025
Actually, I think the proper solution must go deeper. In the end, this is a topic that should be handled within RadialAxis. The locator should always be wrapped in a RadialLocator, so I would say that set_major_locator should be overridden to ensure the wrapping.
There's already a helper function for wrapping:
matplotlib/lib/matplotlib/projections/polar.py
Lines 682 to 685 in f6b77d2
but I'm unclear what the isDefault_majloc is doing and whether we need it. Also, this helper is called explicitly - do we still need that if RadialAxis.set_major_locator will do the wrapping? @QuLogic you seem to have introduced this in #9068 do you still remember?
FIX: Ensure Locators on RadialAxis are always correctly wrapped
FIX: Ensure Locators on RadialAxis are always correctly wrapped
Fix issue matplotlib#30164: Removing spines in polar plot causing dis…
Issue matplotlib#30164: Removing spines causes distortion of the plot
Fix issue matplotlib#30164: Removing spines from polar plot causing d…
Fix issue matplotlib#30164: Removing spines from polar causing distor…
FIX: Ensure Locators on RadialAxis are always correctly wrapped