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.

TypeScript

// 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(): void {
  const map = new google.maps.Map(
    document.getElementById("map") as HTMLElement,
    {
      zoom: 14,
      center: { lat: 34.366, lng: -89.519 }
    }
  );
  const 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", 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: google.maps.LatLng,
  poly: google.maps.Polyline
) {
  const 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
  const encodeString = google.maps.geometry.encoding.encodePath(path);

  if (encodeString) {
    (document.getElementById(
      "encoded-polyline"
    ) as HTMLInputElement).value = encodeString;
  }
}index.ts

JavaScript

// 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() {
  const map = new google.maps.Map(document.getElementById("map"), {
    zoom: 14,
    center: { lat: 34.366, lng: -89.519 }
  });
  const 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", 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) {
  const 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
  const encodeString = google.maps.geometry.encoding.encodePath(path);

  if (encodeString) {
    document.getElementById("encoded-polyline").value = encodeString;
  }
}
index.js

CSS

#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.css

HTML

<!DOCTYPE html>
<html>
  <head>
    <title>Encoding Methods</title>
    <script src="https://polyfill.io/v3/polyfill.min.js?features=default"></script>
    <script
      src="https://maps.googleapis.com/maps/api/js?key=YOUR_API_KEY&callback=initMap&libraries=geometry&v=weekly"
      defer
    ></script>
    <link rel="stylesheet" type="text/css" href="./style.css" />
    <script src="./app.js"></script>
  </head>
  <body>
    <div id="map"></div>
    <div id="right-panel">
      <div>Encoding:</div>
      <textarea id="encoded-polyline"></textarea>
    </div>
  </body>
</html>sample.html

All

<!DOCTYPE html>
<html>
  <head>
    <title>Encoding Methods</title>
    <script src="https://polyfill.io/v3/polyfill.min.js?features=default"></script>
    <script
      src="https://maps.googleapis.com/maps/api/js?key=YOUR_API_KEY&callback=initMap&libraries=geometry&v=weekly"
      defer
    ></script>
    <style type="text/css">
      #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>
    <script>
      "use strict";

      // 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() {
        const map = new google.maps.Map(document.getElementById("map"), {
          zoom: 14,
          center: {
            lat: 34.366,
            lng: -89.519
          }
        });
        const 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", 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) {
        const 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

        const encodeString = google.maps.geometry.encoding.encodePath(path);

        if (encodeString) {
          document.getElementById("encoded-polyline").value = encodeString;
        }
      }
    </script>
  </head>
  <body>
    <div id="map"></div>
    <div id="right-panel">
      <div>Encoding:</div>
      <textarea id="encoded-polyline"></textarea>
    </div>
  </body>
</html>
inline.html

"use strict"; // 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=AIzaSyBIwzALxUPNbatRBj3Xi1Uhp0fFzwWNBkE&libraries=geometry"> function initMap() { const map = new google.maps.Map(document.getElementById("map"), { zoom: 14, center: { lat: 34.366, lng: -89.519 } }); const 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", 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) { const 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 const encodeString = google.maps.geometry.encoding.encodePath(path); if (encodeString) { document.getElementById("encoded-polyline").value = encodeString; } }

#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%; }

<!DOCTYPE html> <html> <head> <title>Encoding Methods</title> <script src="https://polyfill.io/v3/polyfill.min.js?features=default"></script> <script src="https://maps.googleapis.com/maps/api/js?key=AIzaSyBIwzALxUPNbatRBj3Xi1Uhp0fFzwWNBkE&callback=initMap&libraries=geometry&v=weekly" defer ></script>  </head> <body> <div id="map"></div> <div id="right-panel"> <div>Encoding:</div> <textarea id="encoded-polyline"></textarea> </div> </body> </html>

Create a starter application from sample

A skeleton starter application using TypeScript, Webpack, and Babel can be generated from this sample using one of the methods below.

Run Locally

Node.js is required to run this sample locally. Follow these instructions to install Node.js and NPM.

npm i -g '@googlemaps/js-samples'
googlemaps-js-samples init geometry-encodings DESTINATION_FOLDER

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