title: D3 overlay heatmap onto a map
body: <p>I am trying to create a grid heatmap from csv values(with rows, columns, and count) and then overlay the heatmap onto a map(google-maps,or any static map image would also do). The grid is a 2d grid of latitudes and longitudes.Any help would be appreciated.</p>
  
  <p>I have looked at this example <a href="http://bl.ocks.org/mbostock/3202354" rel="nofollow">http://bl.ocks.org/mbostock/3202354</a> , and have an idea of how to draw the heatmap.</p>
  
  <p>I am trying to create something like this: <a href="http://bl.ocks.org/mbostock/4060606" rel="nofollow">http://bl.ocks.org/mbostock/4060606</a> , but dont have the GeoJSON values.</p>