Complex Polylines

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?key=AIzaSyCkUOdZ5y7hMm0yrcCQoCvLwzdM6M8s5qk&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

// This example creates an interactive map which constructs a polyline based on
// user clicks. Note that the polyline only appears once its path property
// contains two LatLng coordinates.

var poly;
var map;

function initMap() {
  map = new google.maps.Map(document.getElementById('map'), {
    zoom: 7,
    center: {lat: 41.879, lng: -87.624}  // Center the map on Chicago, USA.
  });

  poly = new google.maps.Polygon({
  strokeColor: '#00DB00',
          strokeOpacity: 1.0,
          strokeWeight: 3,
          fillColor: 'green',
          fillOpacity: 0.25
  });
  poly.setMap(map);

  // Add a listener for the click event
  map.addListener('click', addLatLng);
}

// Handles click events on a map, and adds a new point to the Polyline.
function addLatLng(event) {
  var path = poly.getPath();

  // Because path is an MVCArray, we can simply append a new coordinate
  // and it will automatically appear.
  path.push(event.latLng);

  // Add a new marker at the new plotted point on the polyline.
  var marker = new google.maps.Marker({
    position: event.latLng,
    title: '#' + path.getLength(),
    map: map
  });
}