[Matplotlib-users] plotting data with nan

[Fabrice S. <si...@lm...>]

Hello,

I want to plot data containing nan values, but it seems that matplotlib
forget some non-nan values near nan values.
In the attached image, I plotted in blue the array for increasing of
x-data, and in red for decreasing x-data : 

import numpy as NX

        In [1]: from pylab import figure, plot, show
        In [2]: figure(2)
        Out[2]: <matplotlib.figure.Figure instance at 0x8445c8c>
        
        In [3]: type(Freq)
        Out[3]: <type 'numpy.ndarray'>
        
        In [4]: NX.any(NX.isnan(Freq))
        Out[4]: True
        
        In [5]: type(Grillefr)
        Out[5]: <type 'numpy.ndarray'>
        
        In [6]: NX.any(NX.isnan(Grillefr))
        Out[6]: False
        
        In [7]: plot(Grillefr, Freq, 'b', lw=2.)
        Out[7]: [<matplotlib.lines.Line2D instance at 0x9245e8c>]
        
        In [8]: plot(Grillefr[::-1], Freq[::-1], 'r', lw=0.5)
        Out[8]: [<matplotlib.lines.Line2D instance at 0x9245fec>]
        
        In [9]: show()
        
with Grillefr containing values from 100 to 2000.
In the matplotlibrc, I have : 
maskedarray  : True

Can anybody explain me why some points are not drawn by matplotlib ?
-- 
Fabrice Silva <si...@lm...>
LMA UPR CNRS 7051 - équipe S2M