title: d3plus.Geomap is not a constructor
body: <p>I am making my first d3plus chart and trying to copy one in here
  <a href="https://d3plus.org/examples/d3plus-geomap/coordinate-points/" rel="nofollow noreferrer">https://d3plus.org/examples/d3plus-geomap/coordinate-points/</a></p>
  
  <p>But unlike highcharts there is very little explanation on how to use the chart.
  My current code is:</p>
  
  <pre><code>&lt;script src="./d3plus.full.min.js"&gt;&lt;/script&gt;
  
  &lt;div id="viz"&gt; &lt;/div&gt;
  
  &lt;script&gt;
  
  new d3plus.Geomap()
    .container("#viz")
    .data("https://d3plus.org/data/city_coords.json")
    .groupBy("slug")
    .colorScale("dma_code")
    .colorScaleConfig({
      color: ["red", "orange", "yellow", "green", "blue"]
    })
    .label(function(d) {
      return d.city + ", " + d.region;
    })
    .point(function(d) {
      return [d.longitude, d.latitude];
    })
    .render();
  
  
    &lt;/script&gt;
  </code></pre>
  
  <hr>
  
  <p>and I am getting error : d3plus.Geomap is not a constructor.
  Can some please tell me my mistake or point me towards basic d3plus examples</p>