Device Orientation

α :

β :

γ :

Listen to DeviceOrientation events.

This example shows how to track changes in device orientation. gyronorm.js library is used to access and normalize the events from the browser.

main.js

import 'ol/ol.css';
import Map from 'ol/Map';
import OSM from 'ol/source/OSM';
import TileLayer from 'ol/layer/Tile';
import View from 'ol/View';
import {toRadians} from 'ol/math';

const view = new View({
  center: [0, 0],
  zoom: 2,
});
const map = new Map({
  layers: [
    new TileLayer({
      source: new OSM(),
    }),
  ],
  target: 'map',
  view: view,
});

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

const gn = new GyroNorm();

gn.init().then(function () {
  gn.start(function (event) {
    const center = view.getCenter();
    const resolution = view.getResolution();
    const alpha = toRadians(event.do.alpha);
    const beta = toRadians(event.do.beta);
    const gamma = toRadians(event.do.gamma);

    el('alpha').innerText = alpha + ' [rad]';
    el('beta').innerText = beta + ' [rad]';
    el('gamma').innerText = gamma + ' [rad]';

    center[0] -= resolution * gamma * 25;
    center[1] += resolution * beta * 25;

    view.setCenter(center);
  });
});

index.html

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8">
    <title>Device Orientation</title>
    <!-- Pointer events polyfill for old browsers, see https://caniuse.com/#feat=pointer -->
    <script src="https://unpkg.com/elm-pep"></script>
    <!-- The line below is only needed for old environments like Internet Explorer and Android 4.x -->
    <script src="https://cdn.polyfill.io/v3/polyfill.min.js?features=fetch,requestAnimationFrame,Element.prototype.classList,URL,TextDecoder,Number.isInteger"></script>
    <script src="https://unpkg.com/gyronorm@2.0.6/dist/gyronorm.complete.min.js"></script>
    <style>
      .map {
        width: 100%;
        height:400px;
      }
    </style>
  </head>
  <body>
    <div id="map" class="map"></div>
    <p>
      <div>α : <code id="alpha"></code></div>
      <div>β : <code id="beta"></code></div>
      <div>γ : <code id="gamma"></code></div>
    </p>
    <script src="main.js"></script>
  </body>
</html>

package.json

{
  "name": "device-orientation",
  "dependencies": {
    "ol": "6.6.1"
  },
  "devDependencies": {
    "parcel": "^2.0.0-beta.1"
  },
  "scripts": {
    "start": "parcel index.html",
    "build": "parcel build --public-url . index.html"
  }
}