Geolocation

track position

position accuracy : altitude : altitude accuracy : heading : speed :

Using geolocation to control a map view.

This example uses the Geolocation API to control the view.

main.js

import Feature from 'ol/Feature.js';
import Geolocation from 'ol/Geolocation.js';
import Map from 'ol/Map.js';
import Point from 'ol/geom/Point.js';
import View from 'ol/View.js';
import {Circle as CircleStyle, Fill, Stroke, Style} from 'ol/style.js';
import {OSM, Vector as VectorSource} from 'ol/source.js';
import {Tile as TileLayer, Vector as VectorLayer} from 'ol/layer.js';

const view = new View({
  center: [0, 0],
  zoom: 2,
});

const map = new Map({
  layers: [
    new TileLayer({
      source: new OSM(),
    }),
  ],
  target: 'map',
  view: view,
});

const geolocation = new Geolocation({
  // enableHighAccuracy must be set to true to have the heading value.
  trackingOptions: {
    enableHighAccuracy: true,
  },
  projection: view.getProjection(),
});

function el(id) {
  return document.getElementById(id);
}

el('track').addEventListener('change', function () {
  geolocation.setTracking(this.checked);
});

// update the HTML page when the position changes.
geolocation.on('change', function () {
  el('accuracy').innerText = geolocation.getAccuracy() + ' [m]';
  el('altitude').innerText = geolocation.getAltitude() + ' [m]';
  el('altitudeAccuracy').innerText = geolocation.getAltitudeAccuracy() + ' [m]';
  el('heading').innerText = geolocation.getHeading() + ' [rad]';
  el('speed').innerText = geolocation.getSpeed() + ' [m/s]';
});

// handle geolocation error.
geolocation.on('error', function (error) {
  const info = document.getElementById('info');
  info.innerHTML = error.message;
  info.style.display = '';
});

const accuracyFeature = new Feature();
geolocation.on('change:accuracyGeometry', function () {
  accuracyFeature.setGeometry(geolocation.getAccuracyGeometry());
});

const positionFeature = new Feature();
positionFeature.setStyle(
  new Style({
    image: new CircleStyle({
      radius: 6,
      fill: new Fill({
        color: '#3399CC',
      }),
      stroke: new Stroke({
        color: '#fff',
        width: 2,
      }),
    }),
  }),
);

geolocation.on('change:position', function () {
  const coordinates = geolocation.getPosition();
  positionFeature.setGeometry(coordinates ? new Point(coordinates) : null);
});

new VectorLayer({
  map: map,
  source: new VectorSource({
    features: [accuracyFeature, positionFeature],
  }),
});

index.html

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8">
    <title>Geolocation</title>
    <link rel="stylesheet" href="node_modules/ol/ol.css">
    <style>
      .map {
        width: 100%;
        height: 400px;
      }
    </style>
  </head>
  <body>
    <div id="map" class="map"></div>
    <div id="info" style="display: none;"></div>
    <label for="track">
      track position
      <input id="track" type="checkbox"/>
    </label>
    <p>
      position accuracy : <code id="accuracy"></code>&nbsp;&nbsp;
      altitude : <code id="altitude"></code>&nbsp;&nbsp;
      altitude accuracy : <code id="altitudeAccuracy"></code>&nbsp;&nbsp;
      heading : <code id="heading"></code>&nbsp;&nbsp;
      speed : <code id="speed"></code>
    </p>

    <script type="module" src="main.js"></script>
  </body>
</html>

package.json

{
  "name": "geolocation",
  "dependencies": {
    "ol": "10.2.1"
  },
  "devDependencies": {
    "vite": "^3.2.3"
  },
  "scripts": {
    "start": "vite",
    "build": "vite build"
  }
}