Polygon

HTML

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

CSS

/* 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;
}

JavaScript

var map;
function initMap() {
  map = new google.maps.Map(document.getElementById('map'), {
    zoom: 15,
    center: {lat: 51.53049469, lng: -0.125664994120598}
  });

  // NOTE: This uses cross-domain XHR, and may not work on older browsers.
  map.data.addGeoJson(JSON.parse('{"type":"FeatureCollection","features":[{"type":"Feature","properties":{"stroke":"#0000ff","fill":"#0000ff","stroke-width":6,"stroke-opacity":1},"geometry":{"type":"Polygon","coordinates":[[[51.533803, -0.127891],  [[51.534007, -0.127183]],  [[51.532285, -0.12586]],[[51.533803, -0.127891]],[[51.533803, -0.127891]]]}}]}'));
}