Moveend Event

left: right: bottom: top:

Use of the moveend event.

In this example, a listener is registered for the map's moveend event. Whenever this listener is called, it updates the inputs below with the map extent in decimal degrees.

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 {getBottomLeft, getTopRight} from 'ol/extent.js';
import {toLonLat} from 'ol/proj.js';

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

function display(id, value) {
  document.getElementById(id).value = value.toFixed(2);
}

function wrapLon(value) {
  const worlds = Math.floor((value + 180) / 360);
  return value - worlds * 360;
}

function onMoveEnd(evt) {
  const map = evt.map;
  const extent = map.getView().calculateExtent(map.getSize());
  const bottomLeft = toLonLat(getBottomLeft(extent));
  const topRight = toLonLat(getTopRight(extent));
  display('left', wrapLon(bottomLeft[0]));
  display('bottom', bottomLeft[1]);
  display('right', wrapLon(topRight[0]));
  display('top', topRight[1]);
}

map.on('moveend', onMoveEnd);

index.html

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8">
    <title>Moveend Event</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>
    <label>left: <input readonly="readonly" type="text" id="left"></label>
    <label>right: <input readonly="readonly" type="text" id="right"></label>
    <label>bottom: <input readonly="readonly" type="text" id="bottom"></label>
    <label>top: <input readonly="readonly" type="text" id="top"></label>

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

package.json

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