title: Using Matplotlib's Hexbin to Create Heatmap
body: <p>I am not a programmer but I have been doing some data analysis using Python lately and recently stumbled across Matplotlib.  I have a series of geo-coordinate data points that I am trying to visualize.  The data consists of geo coordinates and the sqft of each location: </p>
  
  <p>latitude, longitude, SQFT</p>
  
  <p>I have about 25k of these data points and I would like to show the cumulative sqft of these on a 2d image; basically create a heatmap of the sqft.  I have managed to use Matplotlib to create a hexbin with the lat and long data but this only gives me a count of the number of times an item falls into the bin.  I cannot figure out how I incorporate the sqft into the bins.  I have looked at the matplotlib docs and found that I can enter an additional variable, they call C, but I can't figure out how I need to format the data (or if this will even do what I need it to).</p>