title: IndexError when using some projections with basemap and contourf in Python 3.6.1
body: <p>I'm using Python 3.6.1 64bits, Qt 5.6.2, PyQt5 5.6 on Ubuntu 16.4 with Basemap version 1.0.7, matplotlib 2.0.2.  When I try to use a <strong>contourf</strong> with <strong>basemap</strong>, with projection 'cyl', such as:</p>
  
  <pre><code>from mpl_toolkits.basemap import Basemap
  import matplotlib.pyplot as plt
  import numpy as np
  
  map = Basemap(projection='cyl',lat_0=45,lon_0=-100,resolution='c')
  
  nlats = 73; nlons = 145; delta = 2.*np.pi/(nlons-1)
  lats = (0.5*np.pi-delta*np.indices((nlats,nlons))[0,:,:])
  lons = (delta*np.indices((nlats,nlons))[1,:,:])
  wave = 0.75*(np.sin(2.*lats)**8*np.cos(4.*lons))
  mean = 0.5*np.cos(2.*lats)*((np.sin(2.*lats))**2 + 2.)
  
  x, y = map(lons*180./np.pi, lats*180./np.pi)
  
  cs = map.contour(x,y,wave+mean,15,linewidths=1.5)
  plt.show()
  </code></pre>
  
  <p>I get the following error:</p>
  
  <blockquote>
    <p>Traceback (most recent call last):</p>
    
    <p>File "", line 15, in 
        cs = map.contour(x,y,wave+mean,15,linewidths=1.5)</p>
    
    <p>File
    "/home/gab/anaconda3/lib/python3.6/site-packages/mpl_toolkits/basemap/<strong>init</strong>.py",
    line 521, in with_transform
        return plotfunc(self,x,y,data,*args,**kwargs)</p>
    
    <p>File
    "/home/gab/anaconda3/lib/python3.6/site-packages/mpl_toolkits/basemap/<strong>init</strong>.py",
    line 3542, in contour
        xx = x[x.shape[0]/2,:]</p>
    
    <p>IndexError: only integers, slices (<code>:</code>), ellipsis (<code>...</code>),
    numpy.newaxis (<code>None</code>) and integer or boolean arrays are valid indices</p>
  </blockquote>
  
  <p>This error does not happen if I use for instance the projection 'ortho'. I have no problem running this code on Python 2.6. This question seems to be the same as <a href="https://stackoverflow.com/questions/44519804/indexerror-when-with-basemap-contour-when-using-certain-projections">this one</a>, which was not answered.</p>
  
  <p>Any ideas?</p>