Hi Everyone,
I’m trying to make a quiver plot using the example in examples collection.
The documentation says that I can define the arrow units as:
units: [‘width’ | ‘height’ | ‘dots’ | ‘inches’ | ‘x’ | ‘y’ | ‘xy’]so I did:
from pylab import *
from numpy import ma
X,Y = meshgrid( arange(0,2pi,.2),arange(0,2pi,.2) )
U = cos(X)
V = sin(Y)
figure()
M = sqrt(pow(U, 2) + pow(V, 2))
Q = quiver( X, Y, U, V, M, units=‘x’, pivot=‘tip’, width=0.022, scale=1/0.15)
Q = quiver( X, Y, U, V, M, units=‘xy’, pivot=‘tip’, width=0.022, scale=1/0.15)
qk = quiverkey(Q, 0.9, 1.05, 1, r’$1 \frac{m}{s}$’,
labelpos=‘E’,
fontproperties={‘weight’: ‘bold’})
plot(X, Y, ‘k.’)
axis([-1, 7, -1, 7])
title(“scales with x view; pivot=‘tip’”)
show()
When I actually try the option ‘xy’ I get the following error:
Exception in Tkinter callback
Traceback (most recent call last):
File “/usr/lib/python2.6/lib-tk/Tkinter.py”, line 1413, in call
return self.func(*args)
File “/usr/lib/pymodules/python2.6/matplotlib/backends/backend_tkagg.py”, line 212, in resize
self.show()
File “/usr/lib/pymodules/python2.6/matplotlib/backends/backend_tkagg.py”, line 215, in draw
FigureCanvasAgg.draw(self)
File “/usr/lib/pymodules/python2.6/matplotlib/backends/backend_agg.py”, line 314, in draw
self.figure.draw(self.renderer)
File “/usr/lib/pymodules/python2.6/matplotlib/artist.py”, line 46, in draw_wrapper
draw(artist, renderer, *args, **kwargs)
File “/usr/lib/pymodules/python2.6/matplotlib/figure.py”, line 773, in draw
for a in self.axes: a.draw(renderer)
File “/usr/lib/pymodules/python2.6/matplotlib/artist.py”, line 46, in draw_wrapper
draw(artist, renderer, *args, **kwargs)
File “/usr/lib/pymodules/python2.6/matplotlib/axes.py”, line 1735, in draw
a.draw(renderer)
File “/usr/lib/pymodules/python2.6/matplotlib/artist.py”, line 46, in draw_wrapper
draw(artist, renderer, *args, **kwargs)
File “/usr/lib/pymodules/python2.6/matplotlib/quiver.py”, line 436, in draw
self._init()
File “/usr/lib/pymodules/python2.6/matplotlib/quiver.py”, line 425, in _init
trans = self._set_transform()
File “/usr/lib/pymodules/python2.6/matplotlib/quiver.py”, line 481, in _set_transform
raise ValueError('unrecognized units')
ValueError: unrecognized units
Can someone point to where am I mistaken ? Is it a mistake in the documentation ?
Thanks,
···
–
Oz Nahum
Graduate Student
Zentrum für Angewandte Geologie
Universität Tübingen
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