title: How to plot a vector field over a contour plot in matplotlib?
body: <p>I've managed to plot a vector field and a contour plot and would like to display both of them on top of each other, I've looked around but don't quite understand how figure and subplots work. Here is my code: </p>
  
  <pre><code>from matplotlib.pyplot import cm
  import numpy as np
  import matplotlib.pyplot as plt
  
  # Vector Field
  Y, X = np.mgrid[-2:2:20j, -2:2:20j]
  U =(1 - 2*(X**2))*np.exp(-((X**2)+(Y**2)))
  V = -2*X*Y*np.exp(-((X**2)+(Y**2)))
  speed = np.sqrt(U**2 + V**2)
  UN = U/speed
  VN = V/speed
  plt.quiver(X, Y, UN, VN, 
             color='Teal', 
             headlength=7)
  
  plt.show()
  
  
  # Countour Plot
  X, Y = np.mgrid[-2:2:100j, -2:2:100j]
  Z = X*np.exp(-(X**2 + Y**2))
  cp = plt.contourf(X, Y, Z)
  plt.colorbar(cp)
  
  plt.show()
  </code></pre>