title: plot choropleth using google maps
body: <p>I have a data set of <code>{zip code, value}</code> pairs and would like to visualize  it on a map. </p>
  
  <p>Let's say my data set structure is:</p>
  
  <pre><code>{
  "pageType": "ZIP",
  "ZIP": {
      "90638": {
          "OVERALL": "320.00"
      },
      "75594": {
          "OVERALL": "2985.02"
      },
      "10997": {
          "OVERALL": "55554.2"
      }
    }
  }
  </code></pre>
  
  <p>I want to plot this set of zip codes on Google Maps using a colored area corresponding to the zip codes, like on the screenshot below.</p>
  
  <p><a href="https://d3js.org/" rel="nofollow noreferrer">d3js</a> or <a href="http://www.highcharts.com/" rel="nofollow noreferrer">highcharts</a> will not work because they have a location file for a country for plotting the graph. In my case I want to implement it for any country in the world, so I need to use Google Maps.</p>
  
  <p>Any idea
  <a href="https://i.stack.imgur.com/7KmJQ.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/7KmJQ.png" alt="heatmap "></a></p>