title: Python scatter plot with numpy-masked arrays
body: <p>I'm stuck trying to mask data for a scatter plot.  All data seems to plot.</p>
  
  <p>I'm using numpy arrays as shown in the snippet below.  I'm thinking that perhaps I cannot mask on the "c" array.  I can't seem to find any documentation for doing this.  I'll try with the "s" array.</p>
  
  <p>Any help is greatly appreciated.</p>
  
  <hr>
  
  <pre><code>yy = NP.ma.array(yy)
  xx = NP.ma.array(xx)
  zz_masked = NP.ma.masked_where(zz &lt;= 1.0e6 , zz)
  scatter(xx,yy,s=15,c=zz_masked, edgecolors='none')
  cbar = colorbar()
  show()
  </code></pre>