Draw Features

Example of using the ol/interaction/Draw interaction.

Example of using the Draw interaction. Select a geometry type from the dropdown above to start drawing. To finish drawing, click the last point. To activate freehand drawing for lines, polygons, and circles, hold the Shift key. To remove the last point of a line or polygon, press "Undo".

main.js

import 'ol/ol.css';
import Draw from 'ol/interaction/Draw';
import Map from 'ol/Map';
import View from 'ol/View';
import {OSM, Vector as VectorSource} from 'ol/source';
import {Tile as TileLayer, Vector as VectorLayer} from 'ol/layer';

const raster = new TileLayer({
  source: new OSM(),
});

const source = new VectorSource({wrapX: false});

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

const map = new Map({
  layers: [raster, vector],
  target: 'map',
  view: new View({
    center: [-11000000, 4600000],
    zoom: 4,
  }),
});

const typeSelect = document.getElementById('type');

let draw; // global so we can remove it later
function addInteraction() {
  const value = typeSelect.value;
  if (value !== 'None') {
    draw = new Draw({
      source: source,
      type: typeSelect.value,
    });
    map.addInteraction(draw);
  }
}

/**
 * Handle change event.
 */
typeSelect.onchange = function () {
  map.removeInteraction(draw);
  addInteraction();
};

document.getElementById('undo').addEventListener('click', function () {
  draw.removeLastPoint();
});

addInteraction();

index.html

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8">
    <title>Draw 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>
    <form class="form-inline">
      <label for="type">Geometry type: &nbsp;</label>
      <select class="form-control mr-2 mb-2 mt-2" id="type">
        <option value="Point">Point</option>
        <option value="LineString">LineString</option>
        <option value="Polygon">Polygon</option>
        <option value="Circle">Circle</option>
        <option value="None">None</option>
      </select>
      <input class="form-control mr-2 mb-2 mt-2" type="button" value="Undo" id="undo">
    </form>
    <script src="main.js"></script>
  </body>
</html>

package.json

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