title: Python matplotlib uneven spacing y
body: <p>I am wondering how the y axes has such behavior (uneven spacing) without specifying any thing regarding to the yscale as in the following code. </p>
  
  <pre><code>import numpy as np
  import matplotlib.pyplot as plt
  
  
  d=np.zeros([np.arange(0,8).shape[0],np.arange(0,100).shape[0]])
  
  for i in np.arange(0,8):
      for j in np.arange(0,100):
          d[i,j]=(i+290)**2+j**2
  
  c=np.array([1000,850,700,500,400,300,250,200])      
  
  plt.contourf(np.arange(0,100),c,d);plt.colorbar()
  plt.yticks(c,c[::-1])
  plt.show()
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/c9sBj.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/c9sBj.png" alt="enter image description here"></a></p>
  
  <p>Thanks</p>