Moveend Event


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.

<!DOCTYPE html>
<html>
  <head>
    <title>Moveend Event</title>
    <link rel="stylesheet" href="https://openlayers.org/en/v4.6.4/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>
    <script src="https://openlayers.org/en/v4.6.4/build/ol.js"></script>
  </head>
  <body>
    <div id="map" class="map"></div>
    <label>top</label><input type="text" id="top">
    <label>right</label><input type="text" id="right"><br>
    <label>bottom</label><input type="text" id="bottom">
    <label>left</label><input type="text" id="left">
    <script>
      var map = new ol.Map({
        layers: [
          new ol.layer.Tile({
            source: new ol.source.OSM()
          })
        ],
        target: 'map',
        controls: ol.control.defaults({
          attributionOptions: {
            collapsible: false
          }
        }),
        view: new ol.View({
          center: [0, 0],
          zoom: 2
        })
      });

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

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

      function onMoveEnd(evt) {
        var map = evt.map;
        var extent = map.getView().calculateExtent(map.getSize());
        var bottomLeft = ol.proj.transform(ol.extent.getBottomLeft(extent),
            'EPSG:3857', 'EPSG:4326');
        var topRight = ol.proj.transform(ol.extent.getTopRight(extent),
            'EPSG:3857', 'EPSG:4326');
        display('left', wrapLon(bottomLeft[0]));
        display('bottom', bottomLeft[1]);
        display('right', wrapLon(topRight[0]));
        display('top', topRight[1]);
      }

      map.on('moveend', onMoveEnd);
    </script>
  </body>
</html>