Leaflet.GridLayer.GoogleMutant

A LeafletJS plugin to use Google maps basemaps.

Demo

http://ivansanchez.gitlab.io/Leaflet.GridLayer.GoogleMutant/demo.html

Compatibility

• This plugin doesn't work on IE10 or lower, as that browser doesn't implement DOM mutation observers. Chrome, Firefox, Safari, IE11 and Edge are fine.

• IE11 and browsers that don't support Promises need a polyfill in order to work. See the "Known caveats" section.

• The maxNativeZoom functionality introduced in v0.5.0 (thanks, @luiscamacho!) requires Leaflet >1.0.3. At the time of this writing, this means "using the master branch of Leaflet".

Usage

Include the GMaps JS API in your HTML, plus Leaflet:

<script src="https://maps.googleapis.com/maps/api/js?key=YOUR_API_KEY" async defer></script>
<link rel="stylesheet" href="https://unpkg.com/[email protected]/dist/leaflet.css" />
<script src="https://unpkg.com/[email protected]/dist/leaflet.js"></script>

Include the GoogleMutant javascript file:

<script src='https://unpkg.com/leaflet.gridlayer.googlemutant@latest/Leaflet.GoogleMutant.js'></script>

Then, you can create an instance of L.GridLayer.GoogleMutant on your JS code:

var roads = L.gridLayer.googleMutant({
	type: 'roadmap'	// valid values are 'roadmap', 'satellite', 'terrain' and 'hybrid'
}).addTo(map);

It's also possible to use custom styling by passing a value to the styles option, e.g.:

var styled = L.gridLayer.googleMutant({
	type: 'roadmap',
	styles: [
		{elementType: 'labels', stylers: [{visibility: 'off'}]},
		{featureType: 'water', stylers: [{color: '#444444'}]}
	]
}).addTo(map);

Installing a local copy

If you don't want to rely on a CDN to load GoogleMutant, you can:

• Fetch it with NPM by running npm install --save leaflet.gridlayer.googlemutant.
• Fetch it with Yarn by running yarn add leaflet.gridlayer.googlemutant.
• We discourage using Bower but, if you must, bower install https://gitlab.com/IvanSanchez/Leaflet.GridLayer.GoogleMutant.git.

You can also download a static copy from the CDN, or clone this git repo.

Known caveats

• hybrid mode prunes tiles before needed for no apparent reason, so the map flickers when there is a zoom change.

• If you are targeting IE11, then include the following before the script element that references the GoogleMutant javascript file:

<script src="https://unpkg.com/[email protected]/dist/es6-promise.min.js"></script>
<script>ES6Promise.polyfill();</script>

This will polyfill in Javascript Promises for IE.

• GoogleMutant is meant to provide a reliable (and ToC-compliant) way of loading Google Map's tiles into Leaflet, nothing more.

Motivation

Before GoogleMutant, it was already possible to display Google Maps in Leaflet, but unfortunately the state of the art was far from perfect:

• Shramov's Leaflet plugin implementation (as well as an old, not recommended OpenLayers technique) suffer from a big drawback: the basemap and whatever overlays are on top are off sync. This is very noticeable when dragging or zooming.
• MapGear's implementation with OpenLayers uses a different technique (decorate OL3 with GMaps methods), but has a different set of limitations.
• Avin Mathew's implementation uses a clever timer-based technique, but it requires jQuery and still feels jittery due to the timers.

Before, an instance of the Google Maps JS API was displayed behind the Leaflet container, and synchronized as best as it could be done.

Now, in order to provide the best Leaflet experience, GoogleMutant uses both DOM mutation observers and L.GridLayer from Leaflet 1.0.0. The basemap tiles are still requested through the Google maps JavaScript API, but they switch places to use Leaflet drag and zoom.

Legalese

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"THE BEER-WARE LICENSE": [email protected] wrote this file. As long as you retain this notice you can do whatever you want with this stuff. If we meet some day, and you think this stuff is worth it, you can buy me a beer in return.

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