Encoding Methods

This example demonstrates path encoding using the Geometry library. Click the map to create a polyline. The encoding of this polyline then appears in the text box.

Read the documentation.

// This example requires the Geometry library. Include the libraries=geometry
// parameter when you first load the API. For example:
// <script src="https://maps.googleapis.com/maps/api/js?key=YOUR_API_KEY&libraries=geometry">

function initMap() {
  var map = new google.maps.Map(document.getElementById('map'), {
    zoom: 14,
    center: {lat: 34.366, lng: -89.519}
  });
  var poly = new google.maps.Polyline({
    strokeColor: '#000000',
    strokeOpacity: 1,
    strokeWeight: 3,
    map: map
  });

  // Add a listener for the click event
  google.maps.event.addListener(map, 'click', function(event) {
    addLatLngToPoly(event.latLng, poly);
  });
}

/**
 * Handles click events on a map, and adds a new point to the Polyline.
 * Updates the encoding text area with the path's encoded values.
 */
function addLatLngToPoly(latLng, poly) {
  var path = poly.getPath();
  // Because path is an MVCArray, we can simply append a new coordinate
  // and it will automatically appear
  path.push(latLng);

  // Update the text field to display the polyline encodings
  var encodeString = google.maps.geometry.encoding.encodePath(path);
  if (encodeString) {
    document.getElementById('encoded-polyline').value = encodeString;
  }
}
<div id="map"></div>
<div id="right-panel">
  <div>Encoding:</div>
  <textarea id="encoded-polyline"></textarea>
</div>
#right-panel {
  font-family: 'Roboto','sans-serif';
  line-height: 30px;
  padding-left: 10px;
}

#right-panel select, #right-panel input {
  font-size: 15px;
}

#right-panel select {
  width: 100%;
}

#right-panel i {
  font-size: 12px;
}
html, body {
  height: 100%;
  margin: 0;
  padding: 0;
}
#map {
  height: 100%;
  width: 50%;
  float: left;
}
#right-panel {
  width: 46%;
  float: left;
}
#encoded-polyline {
  height: 100px;
  width: 100%;
}
<!-- Replace the value of the key parameter with your own API key. -->
<script src="https://maps.googleapis.com/maps/api/js?key=AIzaSyCkUOdZ5y7hMm0yrcCQoCvLwzdM6M8s5qk&libraries=geometry&callback=initMap"
        async defer></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>
    <title>Encoding Methods</title>
    <meta name="viewport" content="initial-scale=1.0, user-scalable=no">
    <meta charset="utf-8">
    <style>
      #right-panel {
        font-family: 'Roboto','sans-serif';
        line-height: 30px;
        padding-left: 10px;
      }

      #right-panel select, #right-panel input {
        font-size: 15px;
      }

      #right-panel select {
        width: 100%;
      }

      #right-panel i {
        font-size: 12px;
      }
      html, body {
        height: 100%;
        margin: 0;
        padding: 0;
      }
      #map {
        height: 100%;
        width: 50%;
        float: left;
      }
      #right-panel {
        width: 46%;
        float: left;
      }
      #encoded-polyline {
        height: 100px;
        width: 100%;
      }
    </style>
  </head>
  <body>
    <div id="map"></div>
    <div id="right-panel">
      <div>Encoding:</div>
      <textarea id="encoded-polyline"></textarea>
    </div>
    <script>
      // This example requires the Geometry library. Include the libraries=geometry
      // parameter when you first load the API. For example:
      // <script src="https://maps.googleapis.com/maps/api/js?key=YOUR_API_KEY&libraries=geometry">

      function initMap() {
        var map = new google.maps.Map(document.getElementById('map'), {
          zoom: 14,
          center: {lat: 34.366, lng: -89.519}
        });
        var poly = new google.maps.Polyline({
          strokeColor: '#000000',
          strokeOpacity: 1,
          strokeWeight: 3,
          map: map
        });

        // Add a listener for the click event
        google.maps.event.addListener(map, 'click', function(event) {
          addLatLngToPoly(event.latLng, poly);
        });
      }

      /**
       * Handles click events on a map, and adds a new point to the Polyline.
       * Updates the encoding text area with the path's encoded values.
       */
      function addLatLngToPoly(latLng, poly) {
        var path = poly.getPath();
        // Because path is an MVCArray, we can simply append a new coordinate
        // and it will automatically appear
        path.push(latLng);

        // Update the text field to display the polyline encodings
        var encodeString = google.maps.geometry.encoding.encodePath(path);
        if (encodeString) {
          document.getElementById('encoded-polyline').value = encodeString;
        }
      }
    </script>
    <script src="https://maps.googleapis.com/maps/api/js?key=YOUR_API_KEY&libraries=geometry&callback=initMap"
        async defer></script>
  </body>
</html>