polar plot: problem with negative angles

Hello,
in version 0.98.5.2 the polar plot still has a problem with negativ angles.
The polarplot is drawing a circle when the angle changes from negativ to positiv (e.g. from -0.01 to +0.01).

But in “What new in 0.98.4” (http://matplotlib.sourceforge.net/users/whats_new.html) I can read:
“Fix polar interpolation to handle negative values of theta - MGD”

Is there a workaround for this problem?

Regards
Magnus

···

import numpy as np
import matplotlib
import matplotlib.pyplot as plt

x = np.linspace(-np.pi/3, np.pi/3, 100)
y = np.sin((10*x)**2)+2

plt.subplot(111, polar=True)
plt.plot(x,y)
plt.title(matplotlib.version)
plt.show()

Magnus Benjes wrote:

Hello,
in version 0.98.5.2 the polar plot still has a problem with negativ angles.
The polarplot is drawing a circle when the angle changes from negativ to positiv (e.g. from -0.01 to +0.01).

Your example works fine with svn. I don't recall whether the problem was fixed before the last release. I think it was.

But in "What new in 0.98.4" (http://matplotlib.sourceforge.net/users/whats_new.html) I can read:
"Fix polar interpolation to handle negative values of theta - MGD"

I think that commit actually introduced the problem.

Is there a workaround for this problem?

A release appears to be imminent--it was tagged hours ago. Can you update when it appears?

Eric

···

Regards
Magnus
********************
import numpy as np
import matplotlib
import matplotlib.pyplot as plt
x = np.linspace(-np.pi/3, np.pi/3, 100)
y = np.sin((10*x)**2)+2
plt.subplot(111, polar=True)
plt.plot(x,y)
plt.title(matplotlib.__version__)
plt.show()

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Magnus Benjes wrote:

Hello,
in version 0.98.5.2 the polar plot still has a problem with negativ angles.
The polarplot is drawing a circle when the angle changes from negativ to positiv (e.g. from -0.01 to +0.01).

Your example works fine with svn. I don't recall whether the problem was fixed before the last release. I think it was.

Thank you for the hint, in version 0.98.6 the polar plot has no problems with negativ angles any more.
But now there are only gridlines in radial direction and the gridlines in angular direction are missing.

Magnus

The grid line will reappear if you set high enough resolution.

plt.subplot(111, polar=True, resolution=100)

This should be filed as a bug, though.
I guess the current default for resolution is 1. I think this was to
enable to draw a straight line in polar projection. However, my guess
is that it has a side-effect that a angular gridline became a 0-length
line connecting two identical points.

-JJ

···

On Sun, May 17, 2009 at 2:51 PM, Magnus Benjes <magnus.benjes@...982...> wrote:

Magnus Benjes wrote:

Hello,
in version 0.98.5.2 the polar plot still has a problem with negativ
angles.
The polarplot is drawing a circle when the angle changes from negativ to
positiv (e.g. from -0.01 to +0.01).

Your example works fine with svn. I don't recall whether the problem was
fixed before the last release. I think it was.

Thank you for the hint, in version 0.98.6 the polar plot has no problems
with negativ angles any more.
But now there are only gridlines in radial direction and the gridlines in
angular direction are missing.

Magnus

------------------------------------------------------------------------------
Crystal Reports - New Free Runtime and 30 Day Trial
Check out the new simplified licensing option that enables
unlimited royalty-free distribution of the report engine
for externally facing server and web deployment.
http://p.sf.net/sfu/businessobjects
_______________________________________________
Matplotlib-users mailing list
Matplotlib-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/matplotlib-users