Icon modification

Example using a Modify interaction to edit an icon.

The icon on this map can be dragged to modify its location.

The Modify interaction can be configured with a hitDetection option. With this option, the modification candidate will not be determined by the pixelTolerance, but match the visual appearance of the geometry.

main.js

import 'ol/ol.css';
import Feature from 'ol/Feature';
import Map from 'ol/Map';
import Point from 'ol/geom/Point';
import TileJSON from 'ol/source/TileJSON';
import VectorSource from 'ol/source/Vector';
import View from 'ol/View';
import {Icon, Style} from 'ol/style';
import {Modify} from 'ol/interaction';
import {Tile as TileLayer, Vector as VectorLayer} from 'ol/layer';

const iconFeature = new Feature({
  geometry: new Point([0, 0]),
  name: 'Null Island',
  population: 4000,
  rainfall: 500,
});

const iconStyle = new Style({
  image: new Icon({
    anchor: [0.5, 46],
    anchorXUnits: 'fraction',
    anchorYUnits: 'pixels',
    src: 'data/icon.png',
  }),
});

iconFeature.setStyle(iconStyle);

const vectorSource = new VectorSource({
  features: [iconFeature],
});

const vectorLayer = new VectorLayer({
  source: vectorSource,
});

const rasterLayer = new TileLayer({
  source: new TileJSON({
    url: 'https://a.tiles.mapbox.com/v3/aj.1x1-degrees.json?secure=1',
    crossOrigin: '',
  }),
});

const target = document.getElementById('map');
const map = new Map({
  layers: [rasterLayer, vectorLayer],
  target: target,
  view: new View({
    center: [0, 0],
    zoom: 3,
  }),
});

const modify = new Modify({
  hitDetection: vectorLayer,
  source: vectorSource,
});
modify.on(['modifystart', 'modifyend'], function (evt) {
  target.style.cursor = evt.type === 'modifystart' ? 'grabbing' : 'pointer';
});
const overlaySource = modify.getOverlay().getSource();
overlaySource.on(['addfeature', 'removefeature'], function (evt) {
  target.style.cursor = evt.type === 'addfeature' ? 'pointer' : '';
});

map.addInteraction(modify);

index.html

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8">
    <title>Icon modification</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>
    <script src="main.js"></script>
  </body>
</html>

package.json

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