Helpers for Google Maps v3 in Rails - Using html 5, the google maps api v3 and the static maps api
Ruby CoffeeScript JavaScript
Switch branches/tags
Clone or download
Fetching latest commit…
Cannot retrieve the latest commit at this time.
Failed to load latest commit information.

BHM Google Maps

Helpers for Google Maps v3 in Rails - Using html 5, the google maps api v3 and the static maps api Supports unobtrusive maps in Rails 3 (and 2.3, but preferably 3) using the new google maps v3 api.


Installing bhm-google-maps is simple. To get started with a rails 3 app:

  1. Add the gem to your Gemfile: Add gem "bhm-google-maps"
  2. Generate the js into your app: rake bhm-google-maps:install
  3. Configure as needed

Some parts of bhm-google-maps may need to be configured - e.g. out of the box, it will append the google maps js url to the page and the gmap.js from where it was called, as an example of changing this, we suggest creating config/initializers/bhm_google_maps_config.rb and configuring from there. e.g:

# t is the scope of the view / helpers.
# This will append it to a content_for section
# instead of directly in the page.
BHM::GoogleMaps.include_js_proc = proc do |t|
  t.content_for :extra_head, t.javascript_include_tag(t.google_maps_url(false), "gmap.js")

For a fuller / more in depth reference, see configuration below.

If you're using bhm-google-maps with Barista, you can skip the rake bhm-google-maps:install task, it will register itself as a framework with the default output directory.


Currently, bhm-google-maps is designed to show a single map w/ static fallback. To do this, you use the draw_map_of helper. You pass it an object you wish to plot, typically following the convention that:

  1. and object.lng return latitude / longitude respectively
  2. object.to_s returns the string representing the address / the address

Of course, this can be changed via other conventions. For this example, we'll use the following class demo:

class Location
  attr_accessor :address, :lat, :lng
  def initialize(address, lat, lng)
    @address = address
    @lat = lat
    @lng = lng
  def to_s; address.to_s; end

Then, in your view, you could simple call:

<%= draw_map_of"My House", 12.345, 56.789) %>

Optionally, draw_map_of accepts a hash of options for:

  • :static_map_html - options to pass to the image_tag for the static map.
  • :static_map - options to pass to the BHM::GoogleMaps::StaticMap constructor. These include :type, :width and :height
  • :marker - options to pass to the google.maps.Marker in js.

You also get the following helpers:

  • using_gmaps_js? - whether or not the embed method has been called
  • use_gmaps_js - calls your embed method for the js - see configuration.
  • google_maps_url(sensor = false) - returns the url for the google maps api v3.
  • static_map_of_addresses(addresses) - returns an image tag for an array of addresses.
  • static_map_of_address(address) - returns an image tag for a given address


For configuration purposes, there are a set of options on BHM::GoogleMaps. You can set them via BHM::GoogleMaps.option_name = value

  • container_class - the map class for the container div, defaults to gmap. If changed, you must update the js.
  • static_map_class - the class of the container div, removed via js when made dynamic.
  • include_js_proc - how to embed js in the page (e.g. using content_for), defaults to using concat. Is called as a proc w/ the template passed as the only argument.
  • address_to_s_proc - passed an address, converts it to a string (defaults to to_s)
  • address_to_lat_lng_proc - passed an address, returns an array w/ lat and lng.

Ideally these options should be set in an initializer.

Note on Patches/Pull Requests

  1. Fork the project.
  2. Make your feature addition or bug fix.
  3. Add tests for it. This is important so I don't break it in a future version unintentionally.
  4. Commit, do not mess with rakefile, version, or history. (if you want to have your own version, that is fine but bump version in a commit by itself I can ignore when I pull)
  5. Send me a pull request. Bonus points for topic branches.


Copyright (c) 2010 Youth Tree. See LICENSE for details.