title: Plotting a 2D mesh grid with matplotlib
body: <p>I would like to plot a 2D discretization rectangular mesh with non-regular
  x y axes values, e.g. the typical discretization meshes used in CFD.
  An example of the code may be:</p>
  
  <pre><code>    fig = plt.figure(1,figsize=(12,8))
  
      axes = fig.add_subplot(111)
  
      matplotlib.rcParams.update({'font.size':17})
  
      axes.set_xticks(self.xPoints)
      axes.set_yticks(self.yPoints)
  
      plt.grid(color='black', linestyle='-', linewidth=1)
  
      myName = "2D.jpg" 
  
      fig.savefig(myName)
  </code></pre>
  
  <p>where self.xPoints and self.yPoints are 1D non-regular vectors.</p>
  
  <p>This piece of code produce a good discretization mesh, <strong>the problem are the 
  xtics and ytics labels</strong> because they appear for all values of xPoints and yPoints (they overlap). 
  How can I easily redefine the printed values in the axes? 
  Let's say I only want to show the minimum and maximum value for x and y and not all values from the discretization mesh.
  I cann't post a example-figure because it is the first time I ask something here (I can send it by mail if requested)</p>