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

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>
    <link rel="stylesheet" href="node_modules/ol/ol.css">
    <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="https://cdn.jsdelivr.net/npm/[email protected]/dist/gyronorm.complete.min.js"></script>
    <script type="module" src="main.js"></script>
  </body>
</html>

package.json

{
  "name": "device-orientation",
  "dependencies": {
    "ol": "9.1.0"
  },
  "devDependencies": {
    "vite": "^3.2.3"
  },
  "scripts": {
    "start": "vite",
    "build": "vite build"
  }
}