Select multiple Features

0 selected features

Example of selecting multiple features.

In this example, a listener is registered on the map's singleclick event to add and remove features from an array.

main.js

import 'ol/ol.css';
import Fill from 'ol/style/Fill';
import GeoJSON from 'ol/format/GeoJSON';
import Map from 'ol/Map';
import Stroke from 'ol/style/Stroke';
import Style from 'ol/style/Style';
import VectorLayer from 'ol/layer/Vector';
import VectorSource from 'ol/source/Vector';
import View from 'ol/View';
import {fromLonLat} from 'ol/proj';

const highlightStyle = new Style({
  fill: new Fill({
    color: '#EEE',
  }),
  stroke: new Stroke({
    color: '#3399CC',
    width: 2,
  }),
});

const vector = new VectorLayer({
  background: 'white',
  source: new VectorSource({
    url: 'https://openlayers.org/data/vector/us-states.json',
    format: new GeoJSON(),
  }),
});

const map = new Map({
  layers: [vector],
  target: 'map',
  view: new View({
    center: fromLonLat([-100, 38.5]),
    zoom: 4,
    multiWorld: true,
  }),
});

const selected = [];

const status = document.getElementById('status');

map.on('singleclick', function (e) {
  map.forEachFeatureAtPixel(e.pixel, function (f) {
    const selIndex = selected.indexOf(f);
    if (selIndex < 0) {
      selected.push(f);
      f.setStyle(highlightStyle);
    } else {
      selected.splice(selIndex, 1);
      f.setStyle(undefined);
    }
  });

  status.innerHTML = '&nbsp;' + selected.length + ' selected features';
});

index.html

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8">
    <title>Select multiple Features</title>
    <!-- Pointer events polyfill for old browsers, see https://caniuse.com/#feat=pointer -->
    <script src="https://unpkg.com/elm-pep@1.0.6/dist/elm-pep.js"></script>
    <!-- The lines below are only needed for old environments like Internet Explorer and Android 4.x -->
    <script src="https://cdn.polyfill.io/v3/polyfill.min.js?features=fetch,requestAnimationFrame,Element.prototype.classList,TextDecoder"></script>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/core-js/3.18.3/minified.js"></script>
    <style>
      .map {
        width: 100%;
        height:400px;
      }
    </style>
  </head>
  <body>
    <div id="map" class="map"></div>
    <span id="status">&nbsp;0 selected features</span>
    <script src="main.js"></script>
  </body>
</html>

package.json

{
  "name": "select-multiple-features",
  "dependencies": {
    "ol": "6.13.1-dev"
  },
  "devDependencies": {
    "parcel": "^2.0.0"
  },
  "scripts": {
    "start": "parcel index.html",
    "build": "parcel build --public-url . index.html"
  }
}