title: matplotlib imshow display ratio fix to square
body: <p>I have code that produces a plot based on the example below.  I would like to force the outputted plot to be a <code>128x128</code> square if possible instead of <code>64x128</code>.  The data I have is intended to be viewed as a square even though its matrix does not exhibit NxN properties.</p>
  
  <p>Thank you.</p>
  
  <pre><code>import numpy as np
  import pylab as pl
  
  my_matrix = []
  for x in range(128):
      row = []
      for value in range(64):
          row.append( float(value) / 63 )
      my_matrix.append(row)
  
  array = np.matrix(my_matrix)
  pl.axes()
  pl.imshow(array, interpolation='none', cmap='jet', origin='lower')
  pl.colorbar(shrink=0.95)
  pl.xticks(())
  pl.yticks(())
  pl.show()
  </code></pre>