title: matplotlib.pcolor very slow. alternatives?
body: <p>I want to plot a 2D array (roughly 1000x1000) with the values corresponding to a color scale. So I used matplotlib.pcolor, which did just that but for some reason it is super slow when it gets to those dimensions (like 2 minutes or so just to plot). What is the reason for that? Would converting the float values to int16 or so help? Are there any alternatives to pcolor?</p>
  
  <pre><code>from pylab import *
  
  data=genfromtxt('data.txt',autostrip=True, case_sensitive=True)
  pcolor(data,cmap='hot')
  colorbar()
  show()
  </code></pre>
  
  <p>data.txt is containing the array. The loading process does take a few seconds, but the main computing time is definitely used by BOTH the pcolor() and show() function (roughly maybe 60-90 secs each). </p>