matplotlib.pyplot contourf function introduces holes or gaps when plotting regular data

问题

I am trying to plot a 3D dataset using the contourf function in matplotlib.pyplot. All of this is being run inside an iPython notebook. A surface plot of the data looks fine, but the contourf plot has a big hole in it.

A simplified version of the code I am using is:

import numpy as np # import modules
import scipy.io as spio
import matplotlib.pyplot as plt
from mpl_toolkits.mplot3d import Axes3D
fig = plt.figure(figsize=(12,5))
zMin = 1.2
data = spio.loadmat('./OD_SurfMatFiles/surf_k2_c3.mat')
X = data['xVal']
Y = data['yVal']
Z = data['zVal']
plotX, plotY = numpy.meshgrid(X, Y)
ax = fig.add_subplot(1,2,1, projection='3d')
colourLevels = [0.0, 0.4, 0.8, 1.2, 1.6, 2.0, 2.4];
cset = ax.contourf(plotX, plotY, Z, colourLevels, zdir='z',offset=zMin, cmap=cm.autumn)
CB = plt.colorbar(cset, shrink=0.5, extend='both')

The result can be seen here:

http://nbviewer.ipython.org/url/www.alexbaldwin.org.uk/pynotebooks/OD%2520Appendix%2520HM%2520Noise%2520Aperture%2520SurfBug%2520MWE%25202.ipynb

The data that is being plotted is exported from MATLAB:

xVal =

       384   416   448   480   512   544   576   608   640   672

yVal =

    18    19    20    21    22

zVal =

  Columns 1 through 9

    1.1717    1.1421    1.1358    1.2124    1.1721    1.1840    1.1809    1.1399    1.1708
    1.1286    1.2183    1.1654    1.1675    1.1810    1.1745    1.2100    1.2284    1.2096
    1.2132    1.3057    1.2616    1.1742    1.2639    1.2316    1.2039    1.2277    1.2367
    1.2363    1.1987    1.2367    1.2171    1.2718    1.2040    1.2462    1.1802    1.2218
    1.2230    1.2601    1.2411    1.2436    1.2635    1.2197    1.2300    1.2266    1.2368

  Column 10

    1.2357
    1.2039
    1.3010
    1.2273
    1.2336

I originally had this problem with matplotlib 1.2. I considered that they may have fixed it in a later version, but even with u'1.4.x' it still occurs.

来源：https://stackoverflow.com/questions/18897950/matplotlib-pyplot-contourf-function-introduces-holes-or-gaps-when-plotting-regul

标签

python

matplotlib

plot

ipython