Google Maps for Rails Endorse

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Gmaps4rails is developed to simply create a Google Map with overlays (markers, infowindows…). Yet it's backed on a very flexible codebase which could be prone to accept other map providers.

Use it with any Ruby app (I guess you could simply take the js anywhere if you like).

Here is a quick tutorial on youtube, and my presentation on speaker deck.

For live examples, see here.

A note for < 2.x users

Google-Maps-for-Rails-2.0 is an important rewrite to keep the minimum code and features. If you're migrating from previous versions, you may want to read the rational about it.


1) Gemfile

gem 'gmaps4rails'


Add a div to bear your map, example:

<div style='width: 800px;'>
  <div id="map" style='width: 800px; height: 400px;'></div>

2) Javascript Dependencies:

Insert google scripts in your dom:

<script src="//;sensor=false&amp;libraries=geometry" type="text/javascript"></script>
<script src='//' type='text/javascript'></script>

You'll require underscore.js too, see here: (`lo-dash` is compatible too, your choice!).

3) Javascript source code

If you have the asset pipeline, add this:

//= require underscore
//= require gmaps/google

If you don't have asset pipeline, you'll need to import the js OR coffee files:

rails g gmaps4rails:copy_js

rails g gmaps4rails:copy_coffee

4) Javascript code:

Create your map:

handler ='Google');
handler.buildMap({ provider: {}, internal: {id: 'map'}}, function(){
  markers = handler.addMarkers([
      "lat": 0,
      "lng": 0,
      "picture": {
        "url": "",
        "width":  36,
        "height": 36
      "infowindow": "hello!"

Generating JSON

In your controller:

@users = User.all
@hash = Gmaps4rails.build_markers(@users) do |user, marker| user.latitude
  marker.lng user.longitude

In your view:

markers = handler.addMarkers(<%=raw @hash.to_json %>);

Easily customizable

You can change almost everything with a few lines of code. See details here


  • Markers with Info window, Custom Picture, RichMarkers (make your own markers with custom html)

  • Circles, Polylines, Polygons, Kml

  • Refresh your map on the fly with Javascript (and Ajax)

  • More details in the Wiki


Feel free to contact us, you have your say.


MIT license.

Author: Benjamin Roth