Example of a scale line.
<!DOCTYPE html>
<html>
<head>
<title>Scale Line</title>
<link rel="stylesheet" href="https://openlayers.org/en/v5.3.0/css/ol.css" type="text/css">
<!-- 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>
</head>
<body>
<div id="map" class="map"></div>
<select id="units">
<option value="degrees">degrees</option>
<option value="imperial">imperial inch</option>
<option value="us">us inch</option>
<option value="nautical">nautical mile</option>
<option value="metric" selected>metric</option>
</select>
<script>
import Map from 'ol/Map.js';
import View from 'ol/View.js';
import {defaults as defaultControls, ScaleLine} from 'ol/control.js';
import TileLayer from 'ol/layer/Tile.js';
import OSM from 'ol/source/OSM.js';
var scaleLineControl = new ScaleLine();
var map = new Map({
controls: defaultControls().extend([
scaleLineControl
]),
layers: [
new TileLayer({
source: new OSM()
})
],
target: 'map',
view: new View({
center: [0, 0],
zoom: 2
})
});
var unitsSelect = document.getElementById('units');
function onChange() {
scaleLineControl.setUnits(unitsSelect.value);
}
unitsSelect.addEventListener('change', onChange);
onChange();
</script>
</body>
</html>