Circles

This example creates circles on the map, representing populations in North America.

// This example creates circles on the map, representing populations in North
// America.

// First, create an object containing LatLng and population for each city.
var citymap = {
  chicago: {
    center: {lat: 41.878, lng: -87.629},
    population: 2714856
  },
  newyork: {
    center: {lat: 40.714, lng: -74.005},
    population: 8405837
  },
  losangeles: {
    center: {lat: 34.052, lng: -118.243},
    population: 3857799
  },
  vancouver: {
    center: {lat: 49.25, lng: -123.1},
    population: 603502
  }
};

function initMap() {
  // Create the map.
  var map = new google.maps.Map(document.getElementById('map'), {
    zoom: 4,
    center: {lat: 37.090, lng: -95.712},
    mapTypeId: 'terrain'
  });

  // Construct the circle for each value in citymap.
  // Note: We scale the area of the circle based on the population.
  for (var city in citymap) {
    // Add the circle for this city to the map.
    var cityCircle = new google.maps.Circle({
      strokeColor: '#FF0000',
      strokeOpacity: 0.8,
      strokeWeight: 2,
      fillColor: '#FF0000',
      fillOpacity: 0.35,
      map: map,
      center: citymap[city].center,
      radius: Math.sqrt(citymap[city].population) * 100
    });
  }
}

<div id="map"></div>

/* Always set the map height explicitly to define the size of the div
 * element that contains the map. */
#map {
  height: 100%;
}
/* Optional: Makes the sample page fill the window. */
html, body {
  height: 100%;
  margin: 0;
  padding: 0;
}

<!-- Replace the value of the key parameter with your own API key. -->
<script async defer
src="https://maps.googleapis.com/maps/api/js?key=AIzaSyCkUOdZ5y7hMm0yrcCQoCvLwzdM6M8s5qk&callback=initMap">
</script>

Try it yourself

You can experiment with this code in JSFiddle by clicking the <> icon in the top-right corner of the code window.

<!DOCTYPE html>
<html>
  <head>
    <meta name="viewport" content="initial-scale=1.0, user-scalable=no">
    <meta charset="utf-8">
    <title>Circles</title>
    <style>
      /* Always set the map height explicitly to define the size of the div
       * element that contains the map. */
      #map {
        height: 100%;
      }
      /* Optional: Makes the sample page fill the window. */
      html, body {
        height: 100%;
        margin: 0;
        padding: 0;
      }
    </style>
  </head>
  <body>
    <div id="map"></div>
    <script>
      // This example creates circles on the map, representing populations in North
      // America.

      // First, create an object containing LatLng and population for each city.
      var citymap = {
        chicago: {
          center: {lat: 41.878, lng: -87.629},
          population: 2714856
        },
        newyork: {
          center: {lat: 40.714, lng: -74.005},
          population: 8405837
        },
        losangeles: {
          center: {lat: 34.052, lng: -118.243},
          population: 3857799
        },
        vancouver: {
          center: {lat: 49.25, lng: -123.1},
          population: 603502
        }
      };

      function initMap() {
        // Create the map.
        var map = new google.maps.Map(document.getElementById('map'), {
          zoom: 4,
          center: {lat: 37.090, lng: -95.712},
          mapTypeId: 'terrain'
        });

        // Construct the circle for each value in citymap.
        // Note: We scale the area of the circle based on the population.
        for (var city in citymap) {
          // Add the circle for this city to the map.
          var cityCircle = new google.maps.Circle({
            strokeColor: '#FF0000',
            strokeOpacity: 0.8,
            strokeWeight: 2,
            fillColor: '#FF0000',
            fillOpacity: 0.35,
            map: map,
            center: citymap[city].center,
            radius: Math.sqrt(citymap[city].population) * 100
          });
        }
      }
    </script>
    <script async defer
    src="https://maps.googleapis.com/maps/api/js?key=YOUR_API_KEY&callback=initMap">
    </script>
  </body>
</html>