Showing Elevation Along a Path

This example displays a graph that shows the elevation along a path drawn on the map.

Read the documentation.

TypeScript

// Load the Visualization API and the columnchart package.
// @ts-ignore TODO update to newest visualization library
google.load("visualization", "1", { packages: ["columnchart"] });

function initMap(): void {
  // The following path marks a path from Mt. Whitney, the highest point in the
  // continental United States to Badwater, Death Valley, the lowest point.
  const path = [
    { lat: 36.579, lng: -118.292 }, // Mt. Whitney
    { lat: 36.606, lng: -118.0638 }, // Lone Pine
    { lat: 36.433, lng: -117.951 }, // Owens Lake
    { lat: 36.588, lng: -116.943 }, // Beatty Junction
    { lat: 36.34, lng: -117.468 }, // Panama Mint Springs
    { lat: 36.24, lng: -116.832 },
  ]; // Badwater, Death Valley

  const map = new google.maps.Map(
    document.getElementById("map") as HTMLElement,
    {
      zoom: 8,
      center: path[1],
      mapTypeId: "terrain",
    }
  );

  // Create an ElevationService.
  const elevator = new google.maps.ElevationService();

  // Draw the path, using the Visualization API and the Elevation service.
  displayPathElevation(path, elevator, map);
}

function displayPathElevation(
  path: google.maps.LatLngLiteral[],
  elevator: google.maps.ElevationService,
  map: google.maps.Map
) {
  // Display a polyline of the elevation path.
  new google.maps.Polyline({
    path: path,
    strokeColor: "#0000CC",
    strokeOpacity: 0.4,
    map: map,
  });

  // Create a PathElevationRequest object using this array.
  // Ask for 256 samples along that path.
  // Initiate the path request.
  elevator
    .getElevationAlongPath({
      path: path,
      samples: 256,
    })
    .then(plotElevation)
    .catch((e) => {
      const chartDiv = document.getElementById(
        "elevation_chart"
      ) as HTMLElement;

      // Show the error code inside the chartDiv.
      chartDiv.innerHTML = "Cannot show elevation: request failed because " + e;
    });
}

// Takes an array of ElevationResult objects, draws the path on the map
// and plots the elevation profile on a Visualization API ColumnChart.
function plotElevation({ results }: google.maps.PathElevationResponse) {
  const chartDiv = document.getElementById("elevation_chart") as HTMLElement;

  // Create a new chart in the elevation_chart DIV.
  const chart = new google.visualization.ColumnChart(chartDiv);

  // Extract the data from which to populate the chart.
  // Because the samples are equidistant, the 'Sample'
  // column here does double duty as distance along the
  // X axis.
  const data = new google.visualization.DataTable();

  data.addColumn("string", "Sample");
  data.addColumn("number", "Elevation");

  for (let i = 0; i < results.length; i++) {
    data.addRow(["", results[i].elevation]);
  }

  // Draw the chart using the data within its DIV.
  chart.draw(data, {
    height: 150,
    legend: "none",
    // @ts-ignore TODO update to newest visualization library
    titleY: "Elevation (m)",
  });
}

declare global {
  interface Window {
    initMap: () => void;
  }
}
window.initMap = initMap;
index.ts

JavaScript

// Load the Visualization API and the columnchart package.
// @ts-ignore TODO update to newest visualization library
google.load("visualization", "1", { packages: ["columnchart"] });

function initMap() {
  // The following path marks a path from Mt. Whitney, the highest point in the
  // continental United States to Badwater, Death Valley, the lowest point.
  const path = [
    { lat: 36.579, lng: -118.292 }, // Mt. Whitney
    { lat: 36.606, lng: -118.0638 }, // Lone Pine
    { lat: 36.433, lng: -117.951 }, // Owens Lake
    { lat: 36.588, lng: -116.943 }, // Beatty Junction
    { lat: 36.34, lng: -117.468 }, // Panama Mint Springs
    { lat: 36.24, lng: -116.832 },
  ]; // Badwater, Death Valley
  const map = new google.maps.Map(document.getElementById("map"), {
    zoom: 8,
    center: path[1],
    mapTypeId: "terrain",
  });
  // Create an ElevationService.
  const elevator = new google.maps.ElevationService();

  // Draw the path, using the Visualization API and the Elevation service.
  displayPathElevation(path, elevator, map);
}

function displayPathElevation(path, elevator, map) {
  // Display a polyline of the elevation path.
  new google.maps.Polyline({
    path: path,
    strokeColor: "#0000CC",
    strokeOpacity: 0.4,
    map: map,
  });
  // Create a PathElevationRequest object using this array.
  // Ask for 256 samples along that path.
  // Initiate the path request.
  elevator
    .getElevationAlongPath({
      path: path,
      samples: 256,
    })
    .then(plotElevation)
    .catch((e) => {
      const chartDiv = document.getElementById("elevation_chart");

      // Show the error code inside the chartDiv.
      chartDiv.innerHTML = "Cannot show elevation: request failed because " + e;
    });
}

// Takes an array of ElevationResult objects, draws the path on the map
// and plots the elevation profile on a Visualization API ColumnChart.
function plotElevation({ results }) {
  const chartDiv = document.getElementById("elevation_chart");
  // Create a new chart in the elevation_chart DIV.
  const chart = new google.visualization.ColumnChart(chartDiv);
  // Extract the data from which to populate the chart.
  // Because the samples are equidistant, the 'Sample'
  // column here does double duty as distance along the
  // X axis.
  const data = new google.visualization.DataTable();

  data.addColumn("string", "Sample");
  data.addColumn("number", "Elevation");

  for (let i = 0; i < results.length; i++) {
    data.addRow(["", results[i].elevation]);
  }

  // Draw the chart using the data within its DIV.
  chart.draw(data, {
    height: 150,
    legend: "none",
    // @ts-ignore TODO update to newest visualization library
    titleY: "Elevation (m)",
  });
}

window.initMap = initMap;
index.js

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;
}

style.css

HTML

<html>
  <head>
    <title>Showing Elevation Along a Path</title>

    <script src="https://www.google.com/jsapi"></script>

    <link rel="stylesheet" type="text/css" href="./style.css" />
    <script type="module" src="./index.js"></script>
  </head>
  <body>
    <div>
      <div id="map" style="height: 250px"></div>
      <div id="elevation_chart"></div>
    </div>

    <!-- 
      The `defer` attribute causes the script to execute after the full HTML
      document has been parsed. For non-blocking uses, avoiding race conditions,
      and consistent behavior across browsers, consider loading using Promises. See
      https://developers.google.com/maps/documentation/javascript/load-maps-js-api
      for more information.
      -->
    <script
      src="https://maps.googleapis.com/maps/api/js?key=AIzaSyB41DRUbKWJHPxaFjMAwdrzWzbVKartNGg&callback=initMap&v=weekly"
      defer
    ></script>
  </body>
</html>
index.html

Try Sample

Clone Sample

Git and Node.js are required to run this sample locally. Follow these instructions to install Node.js and NPM. The following commands clone, install dependencies and start the sample application. 

  git clone -b sample-elevation-paths https://github.com/googlemaps/js-samples.git
  cd js-samples
  npm i
  npm start

Other samples can be tried by switching to any branch beginning with sample-SAMPLE_NAME. 

  git checkout sample-SAMPLE_NAME
  npm i
  npm start