Edit

Layer Groups

Click on layer nodes below to change their properties.
  • OSM layer
  • Layer group
    • Food insecurity layer
    • World borders layer

Example of a map with layer group.

Example of a map with layer group.

Copy 
index.html<!DOCTYPE html>
<html lang="en">
  <head>
    <title>Layer Groups</title>
    <!-- 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://code.jquery.com/jquery-2.2.3.min.js"></script>
    <style>
      .map {
        width: 100%;
        height:400px;
      }
      #layertree li > span {
        cursor: pointer;
      }    </style>
  </head>
  <body>
    <div id="map" class="map"></div>
    <div id="layertree">
      <h5>Click on layer nodes below to change their properties.</h5>
      <ul>
        <li><span>OSM layer</span>
          <fieldset id="layer0">
            <label class="checkbox" for="visible0">
              <input id="visible0" class="visible" type="checkbox"/>visibility
            </label>
            <label>opacity</label>
            <input class="opacity" type="range" min="0" max="1" step="0.01"/>
          </fieldset>
        </li>
        <li><span>Layer group</span>
          <fieldset id="layer1">
            <label class="checkbox" for="visible1">
              <input id="visible1" class="visible" type="checkbox"/>visibility
            </label>
            <label>opacity</label>
            <input class="opacity" type="range" min="0" max="1" step="0.01"/>
          </fieldset>
          <ul>
            <li><span>Food insecurity layer</span>
              <fieldset id="layer10">
                <label class="checkbox" for="visible10">
                  <input id="visible10" class="visible" type="checkbox"/>visibility
                </label>
                <label>opacity</label>
                <input class="opacity" type="range" min="0" max="1" step="0.01"/>
              </fieldset>
            </li>
            <li><span>World borders layer</span>
              <fieldset id="layer11">
                <label class="checkbox" for="visible11">
                  <input id="visible11" class="visible" type="checkbox"/>visibility
                </label>
                <label>opacity</label>
                <input class="opacity" type="range" min="0" max="1" step="0.01"/>
              </fieldset>
            </li>
          </ul>
        </li>
      </ul>
    </div>
    <script src="index.js"></script>
  </body>
</html>
Copy 
index.jsimport 'ol/ol.css';
import Map from 'ol/Map';
import View from 'ol/View';
import {Group as LayerGroup, Tile as TileLayer} from 'ol/layer';
import {fromLonLat} from 'ol/proj';
import OSM from 'ol/source/OSM';
import TileJSON from 'ol/source/TileJSON';

var key = 'Your Mapbox access token from https://mapbox.com/ here';

var map = new Map({
  layers: [
    new TileLayer({
      source: new OSM()
    }), new LayerGroup({
      layers: [
        new TileLayer({
          source: new TileJSON({
            url: 'https://api.tiles.mapbox.com/v4/mapbox.20110804-hoa-foodinsecurity-3month.json?secure&access_token=' + key,
            crossOrigin: 'anonymous'
          })
        }),
        new TileLayer({
          source: new TileJSON({
            url: 'https://api.tiles.mapbox.com/v4/mapbox.world-borders-light.json?secure&access_token=' + key,
            crossOrigin: 'anonymous'
          })
        })
      ]
    })
  ],
  target: 'map',
  view: new View({
    center: fromLonLat([37.40570, 8.81566]),
    zoom: 4
  })
});

function bindInputs(layerid, layer) {
  var visibilityInput = $(layerid + ' input.visible');
  visibilityInput.on('change', function() {
    layer.setVisible(this.checked);
  });
  visibilityInput.prop('checked', layer.getVisible());

  var opacityInput = $(layerid + ' input.opacity');
  opacityInput.on('input change', function() {
    layer.setOpacity(parseFloat(this.value));
  });
  opacityInput.val(String(layer.getOpacity()));
}
map.getLayers().forEach(function(layer, i) {
  bindInputs('#layer' + i, layer);
  if (layer instanceof LayerGroup) {
    layer.getLayers().forEach(function(sublayer, j) {
      bindInputs('#layer' + i + j, sublayer);
    });
  }
});

$('#layertree li > span').click(function() {
  $(this).siblings('fieldset').toggle();
}).siblings('fieldset').hide();
Copy 
package.json{
  "name": "layer-group",
  "dependencies": {
    "ol": "6.1.1"
  },
  "devDependencies": {
    "parcel": "1.11.0"
  },
  "scripts": {
    "start": "parcel index.html",
    "build": "parcel build --experimental-scope-hoisting --public-url . index.html"
  }
}