Extent Interaction

This example uses OpenLayers v4.0.1. The latest is v.

#### Extent Interaction

Using an Extent interaction to draw an extent.

This example shows how to use an `Extent` interaction to draw a modifiable extent.

Use `Shift+Drag` to draw an extent. `Shift+Drag` on the corners or edges of the extent to resize it. `Shift+Click` off the extent to remove it.

Related API documentation:

- ol.Map
,
- ol.View
,
- ol.events.condition
,
- ol.format.GeoJSON
,
- ol.interaction.Extent
,
- ol.layer.Tile
,
- ol.layer.Vector
,
- ol.source.OSM
,
- ol.source.Vector

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Extent Interaction Using an Extent interaction to draw an extent. var vectorSource = new ol.source.Vector({ url: 'https://openlayers.org/en/v4.0.1/examples/data/geojson/countries.geojson', format: new ol.format.GeoJSON() }); var map = new ol.Map({ layers: [ new ol.layer.Tile({ source: new ol.source.OSM() }), new ol.layer.Vector({ source: vectorSource }) ], target: 'map', view: new ol.View({ center: [0, 0], zoom: 2 }) }); var extent = new ol.interaction.Extent({ condition: ol.events.condition.platformModifierKeyOnly }); map.addInteraction(extent); extent.setActive(false); //Enable interaction by holding shift this.addEventListener('keydown', function(event) { if (event.keyCode == 16) { extent.setActive(true); } }); this.addEventListener('keyup', function(event) { if (event.keyCode == 16) { extent.setActive(false); } }); <div id="map" class="map"></div>

    <!DOCTYPE html>
    <html>
      <head>
        <title>Extent Interaction</title>
        <link rel="stylesheet" href="https://openlayers.org/en/v4.0.1/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/v4.0.1/build/ol.js"></script>
      </head>
      <body>
        <div id="map" class="map"></div>
        <script>
          var vectorSource = new ol.source.Vector({
            url: 'https://openlayers.org/en/v4.0.1/examples/data/geojson/countries.geojson',
            format: new ol.format.GeoJSON()
          });

          var map = new ol.Map({
            layers: [
              new ol.layer.Tile({
                source: new ol.source.OSM()
              }),
              new ol.layer.Vector({
                source: vectorSource
              })
            ],
            target: 'map',
            view: new ol.View({
              center: [0, 0],
              zoom: 2
            })
          });

          var extent = new ol.interaction.Extent({
            condition: ol.events.condition.platformModifierKeyOnly
          });
          map.addInteraction(extent);
          extent.setActive(false);

          //Enable interaction by holding shift
          this.addEventListener('keydown', function(event) {
            if (event.keyCode == 16) {
              extent.setActive(true);
            }
          });
          this.addEventListener('keyup', function(event) {
            if (event.keyCode == 16) {
              extent.setActive(false);
            }
          });
        </script>
      </body>
    </html>