title: How to 'turn off' blurry effect of imshow() in matplotlib?
body: <p>I want to make a color plot of probabilities however imshow generates blurry values for points which have zero probability. How can I get rid of this blurry periphery around real grid points?</p>
  
  <p>Example:</p>
  
  <pre><code>import numpy as np
  import matplotlib.pyplot as plt
  
  a=np.asarray([[  0.00000000e+00 , 1.05824446e-01 ,  2.05086136e-04,   0.00000000e+00],
  [  1.05824446e-01 ,  3.15012305e-01  , 1.31255127e-01  , 1.05209188e-01],
   [  2.05086136e-04  , 1.31255127e-01 ,  0.00000000e+00 ,  0.00000000e+00],
   [  0.00000000e+00   ,1.05209188e-01  , 0.00000000e+00  , 0.00000000e+00]])
  im=plt.imshow(a,extent=[0,4,0,4],origin='lower',alpha=1,aspect='auto')
  plt.show()
  </code></pre>
  
  <p><img src="https://i.stack.imgur.com/ROvz6.png" alt="enter image description here"></p>