Edit

Icon Symbolizer

Example using an icon to symbolize a point.

Example using an icon to symbolize a point.

Copy 
index.html<!DOCTYPE html>
<html lang="en">
  <head>
    <title>Icon Symbolizer</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>
    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css">
    <script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/js/bootstrap.min.js"></script>
    <style>
      .map {
        width: 100%;
        height:400px;
      }
    </style>
  </head>
  <body>
    <div id="map" class="map"><div id="popup"></div></div>
    <script src="index.js"></script>
  </body>
</html>
Copy 
index.jsimport 'ol/ol.css';
import Feature from 'ol/Feature';
import Map from 'ol/Map';
import Overlay from 'ol/Overlay';
import View from 'ol/View';
import Point from 'ol/geom/Point';
import {Tile as TileLayer, Vector as VectorLayer} from 'ol/layer';
import TileJSON from 'ol/source/TileJSON';
import VectorSource from 'ol/source/Vector';
import {Icon, Style} from 'ol/style';


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

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

iconFeature.setStyle(iconStyle);

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

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

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

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

var element = document.getElementById('popup');

var popup = new Overlay({
  element: element,
  positioning: 'bottom-center',
  stopEvent: false,
  offset: [0, -50]
});
map.addOverlay(popup);

// display popup on click
map.on('click', function(evt) {
  var feature = map.forEachFeatureAtPixel(evt.pixel,
    function(feature) {
      return feature;
    });
  if (feature) {
    var coordinates = feature.getGeometry().getCoordinates();
    popup.setPosition(coordinates);
    $(element).popover({
      placement: 'top',
      html: true,
      content: feature.get('name')
    });
    $(element).popover('show');
  } else {
    $(element).popover('destroy');
  }
});

// change mouse cursor when over marker
map.on('pointermove', function(e) {
  if (e.dragging) {
    $(element).popover('destroy');
    return;
  }
  var pixel = map.getEventPixel(e.originalEvent);
  var hit = map.hasFeatureAtPixel(pixel);
  map.getTarget().style.cursor = hit ? 'pointer' : '';
});
Copy 
package.json{
  "name": "icon",
  "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"
  }
}