Geolocation

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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.

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index.html<!DOCTYPE html>
<html lang="en">
  <head>
    <title>Geolocation</title>
    <!-- The line below is only needed for old environments like Internet Explorer and Android 4.x -->
    <script src="https://cdn.polyfill.io/v2/polyfill.min.js?features=requestAnimationFrame,Element.prototype.classList,URL"></script>
    <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 src="index.js"></script>
  </body>
</html>

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

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

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

var 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) {
  var info = document.getElementById('info');
  info.innerHTML = error.message;
  info.style.display = '';
});

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

var 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() {
  var coordinates = geolocation.getPosition();
  positionFeature.setGeometry(coordinates ?
    new Point(coordinates) : null);
});

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

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package.json{
  "name": "geolocation",
  "dependencies": {
    "ol": "6.1.1"
  },
  "devDependencies": {
    "parcel": "1.11.0"
  },
  "scripts": {
    "start": "parcel index.html",
    "build": "parcel build --experimental-scope-hoisting --public-url . index.html"
  }
}