title: numpy histogram with 3 variables
body: <p>Please forgive me if this is a repeated question, I've done my best to look for a solution.  This seems very straightforward but I can't seem to find anything applicable.</p>
  
  <p>I'm trying to generate a plot (like a heatmap) using data from 3 1-D numpy arrays.  The data is basically arranged as follows:</p>
  
  <pre><code>x_axis = ([1, 4, 6])
  y_axis = ([2, 5, 7])
  z_axis = ([5, 8, 9])
  </code></pre>
  
  <p>(my data sets are actually much larger... sometimes hundreds of thousands of entries).</p>
  
  <p>so I've got z_axis values that are each associated with an x-coordinate and y-coordinate... for example, the point (1,2) has the value 5 associated with it.  </p>
  
  <p>All I want to do is plot this in such a way that the z values are averaged out for whatever bin size I specify, and color-coded like a heatmap.   So, for instance, if I've got 10 data points that fall within a given bin, their z-values will be averaged and that value will fall somewhere on a color spectrum.</p>
  
  <p>Thanks for any help you can provide.</p>