Customizing a Google Map: Custom Markers

Select platform: Android iOS JavaScript

Overview

This tutorial teaches you how to change the icon of a Google maps marker. It is beneficial to know the basics of creating markers when using this tutorial.

The following map is an example of a map that uses customized markers.

The section below lists all of the code that you need to create the map in this tutorial.

TypeScript

let map: google.maps.Map;

function initMap(): void {
  map = new google.maps.Map(document.getElementById("map") as HTMLElement, {
    center: new google.maps.LatLng(-33.91722, 151.23064),
    zoom: 16,
  });

  const iconBase =
    "https://developers.google.com/maps/documentation/javascript/examples/full/images/";

  const icons: Record<string, { icon: string }> = {
    parking: {
      icon: iconBase + "parking_lot_maps.png",
    },
    library: {
      icon: iconBase + "library_maps.png",
    },
    info: {
      icon: iconBase + "info-i_maps.png",
    },
  };

  const features = [
    {
      position: new google.maps.LatLng(-33.91721, 151.2263),
      type: "info",
    },
    {
      position: new google.maps.LatLng(-33.91539, 151.2282),
      type: "info",
    },
    {
      position: new google.maps.LatLng(-33.91747, 151.22912),
      type: "info",
    },
    {
      position: new google.maps.LatLng(-33.9191, 151.22907),
      type: "info",
    },
    {
      position: new google.maps.LatLng(-33.91725, 151.23011),
      type: "info",
    },
    {
      position: new google.maps.LatLng(-33.91872, 151.23089),
      type: "info",
    },
    {
      position: new google.maps.LatLng(-33.91784, 151.23094),
      type: "info",
    },
    {
      position: new google.maps.LatLng(-33.91682, 151.23149),
      type: "info",
    },
    {
      position: new google.maps.LatLng(-33.9179, 151.23463),
      type: "info",
    },
    {
      position: new google.maps.LatLng(-33.91666, 151.23468),
      type: "info",
    },
    {
      position: new google.maps.LatLng(-33.916988, 151.23364),
      type: "info",
    },
    {
      position: new google.maps.LatLng(-33.91662347903106, 151.22879464019775),
      type: "parking",
    },
    {
      position: new google.maps.LatLng(-33.916365282092855, 151.22937399734496),
      type: "parking",
    },
    {
      position: new google.maps.LatLng(-33.91665018901448, 151.2282474695587),
      type: "parking",
    },
    {
      position: new google.maps.LatLng(-33.919543720969806, 151.23112279762267),
      type: "parking",
    },
    {
      position: new google.maps.LatLng(-33.91608037421864, 151.23288232673644),
      type: "parking",
    },
    {
      position: new google.maps.LatLng(-33.91851096391805, 151.2344058214569),
      type: "parking",
    },
    {
      position: new google.maps.LatLng(-33.91818154739766, 151.2346203981781),
      type: "parking",
    },
    {
      position: new google.maps.LatLng(-33.91727341958453, 151.23348314155578),
      type: "library",
    },
  ];

  // Create markers.
  for (let i = 0; i < features.length; i++) {
    const marker = new google.maps.Marker({
      position: features[i].position,
      icon: icons[features[i].type].icon,
      map: map,
    });
  }
}

declare global {
  interface Window {
    initMap: () => void;
  }
}
window.initMap = initMap;index.ts

JavaScript

let map;

function initMap() {
  map = new google.maps.Map(document.getElementById("map"), {
    center: new google.maps.LatLng(-33.91722, 151.23064),
    zoom: 16,
  });

  const iconBase =
    "https://developers.google.com/maps/documentation/javascript/examples/full/images/";
  const icons = {
    parking: {
      icon: iconBase + "parking_lot_maps.png",
    },
    library: {
      icon: iconBase + "library_maps.png",
    },
    info: {
      icon: iconBase + "info-i_maps.png",
    },
  };
  const features = [
    {
      position: new google.maps.LatLng(-33.91721, 151.2263),
      type: "info",
    },
    {
      position: new google.maps.LatLng(-33.91539, 151.2282),
      type: "info",
    },
    {
      position: new google.maps.LatLng(-33.91747, 151.22912),
      type: "info",
    },
    {
      position: new google.maps.LatLng(-33.9191, 151.22907),
      type: "info",
    },
    {
      position: new google.maps.LatLng(-33.91725, 151.23011),
      type: "info",
    },
    {
      position: new google.maps.LatLng(-33.91872, 151.23089),
      type: "info",
    },
    {
      position: new google.maps.LatLng(-33.91784, 151.23094),
      type: "info",
    },
    {
      position: new google.maps.LatLng(-33.91682, 151.23149),
      type: "info",
    },
    {
      position: new google.maps.LatLng(-33.9179, 151.23463),
      type: "info",
    },
    {
      position: new google.maps.LatLng(-33.91666, 151.23468),
      type: "info",
    },
    {
      position: new google.maps.LatLng(-33.916988, 151.23364),
      type: "info",
    },
    {
      position: new google.maps.LatLng(-33.91662347903106, 151.22879464019775),
      type: "parking",
    },
    {
      position: new google.maps.LatLng(-33.916365282092855, 151.22937399734496),
      type: "parking",
    },
    {
      position: new google.maps.LatLng(-33.91665018901448, 151.2282474695587),
      type: "parking",
    },
    {
      position: new google.maps.LatLng(-33.919543720969806, 151.23112279762267),
      type: "parking",
    },
    {
      position: new google.maps.LatLng(-33.91608037421864, 151.23288232673644),
      type: "parking",
    },
    {
      position: new google.maps.LatLng(-33.91851096391805, 151.2344058214569),
      type: "parking",
    },
    {
      position: new google.maps.LatLng(-33.91818154739766, 151.2346203981781),
      type: "parking",
    },
    {
      position: new google.maps.LatLng(-33.91727341958453, 151.23348314155578),
      type: "library",
    },
  ];

  // Create markers.
  for (let i = 0; i < features.length; i++) {
    const marker = new google.maps.Marker({
      position: features[i].position,
      icon: icons[features[i].type].icon,
      map: map,
    });
  }
}

window.initMap = initMap;index.js

CSS

/* 
 * Always set the map height explicitly to define the size of the div element
 * that contains the map. 
 */
#map {
  height: 100%;
}

/* 
 * Optional: Makes the sample page fill the window. 
 */
html,
body {
  height: 100%;
  margin: 0;
  padding: 0;
}
style.css

HTML

<html>
  <head>
    <title>Custom Markers</title>
    <script src="https://polyfill.io/v3/polyfill.min.js?features=default"></script>

    <link rel="stylesheet" type="text/css" href="./style.css" />
    <script type="module" src="./index.js"></script>
  </head>
  <body>
    <div id="map"></div>

    <!-- 
      The `defer` attribute causes the callback to execute after the full HTML
      document has been parsed. For non-blocking uses, avoiding race conditions,
      and consistent behavior across browsers, consider loading using Promises.
      See https://developers.google.com/maps/documentation/javascript/load-maps-js-api
      for more information.
      -->
    <script
      src="https://maps.googleapis.com/maps/api/js?key=AIzaSyB41DRUbKWJHPxaFjMAwdrzWzbVKartNGg&callback=initMap&v=weekly"
      defer
    ></script>
  </body>
</html>index.html

Try Sample

JSFiddle.net CodeSandbox.io Google Cloud Shell

Customizing a map marker

The image below displays a Google maps marker with the default red icon.

You can change this icon to an image of your choice. The table below explains the code that customizes the default marker to use an icon for parking lots.

Code and description
`var iconBase = 'https://maps.google.com/mapfiles/kml/shapes/'; var marker = new google.maps.Marker({ position: myLatLng, map: map, icon: iconBase + 'parking_lot_maps.png' });`	Adds the `icon` property to the `MarkerOptions` object, to change the marker’s icon. The `icon` property can be either a string (the URL to the marker icon), or an `Icon` object. See the customized marker icon below.

Customizing markers by map features

Each point of interest in the list of campus features has a type attribute. Notice how the code extract below specifies the parking, library and info types. You can customize the marker icon depending on the map feature type you set it to.

var iconBase = 'https://maps.google.com/mapfiles/kml/shapes/';
var icons = {
  parking: {
    icon: iconBase + 'parking_lot_maps.png'
  },
  library: {
    icon: iconBase + 'library_maps.png'
  },
  info: {
    icon: iconBase + 'info-i_maps.png'
  }
};

function addMarker(feature) {
  var marker = new google.maps.Marker({
    position: feature.position,
    icon: icons[feature.type].icon,
    map: map
  });
}

More information

The image on a marker is called its 'icon'.
A marker is also known as a 'pin'.