You're all set!

To start developing, please head over to our developer documentation.

Activate the Google Maps JavaScript API

To get you started we'll guide you through the Google Developers Console to do a few things first:

  1. Create or choose a project
  2. Activate the Google Maps JavaScript API and related services
  3. Create appropriate keys
Continue

Circles

Read the documentation or view this example full screen.

// 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: google.maps.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>
html, body {
  height: 100%;
  margin: 0;
  padding: 0;
}
#map {
  height: 100%;
}
<!-- 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>
JavaScript
// 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: google.maps.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
    });
  }
}
JavaScript + HTML
<!DOCTYPE html>
<html>
  <head>
    <meta name="viewport" content="initial-scale=1.0, user-scalable=no">
    <meta charset="utf-8">
    <title>Circles</title>
    <style>
      html, body {
        height: 100%;
        margin: 0;
        padding: 0;
      }
      #map {
        height: 100%;
      }
    </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: google.maps.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>

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