Google Maps in Ruby on Rails
To generate google maps in ruby on rails is so easy and simple. I had recently generated a few maps in my projects by YM4R/GM plugin.
Note: to support rails 3 application, certain changes are required in plugin. Those changes listed out here
There are few steps that you need to follow to generate simple gmap.
1. Install YM4R/GM plugin in your rails app.
ruby script/plugin install svn://rubyforge.org/var/svn/ym4r/Plugins/GM/trunk/ym4r_gm
2. Copy the javascripts files from YM4R/GM plugin to public/javascript folder
3. Copy the gmaps_api_key.yml.example file to config folder and rename to gmaps_api_key.yml. Set the api key in that YML file.
If application is in development mode then no necessary to change it.
4. Add below code in your controller.
def gmap
@map = GMap.new("map_div")
@map.control_init(:large_map => true,:map_type => true)
@map.center_zoom_init([22.792388,79.497070],4)
@map.overlay_init(GMarker.new([22.792388,79.497070],:title =>"India", :info_window =>"India"))
@map.record_init @map.add_overlay(GMarker.new([22.792388, 72.421875],:title =>"Ahmedabad", :info_window =>"Ahmedabad"))
end
#control_init : By default false.
:large_map: true means you can get options of zoom in /zoom out of map on left side of map.
:map_type: true means you can change the type of map.
#center_zoom_init: Set the center point of map.
#overlay_init: Mark the position on map.
#record_init @map.add_overlay: Mark more position on map.
5. Add below code in your view.
<html><head><title>Test</title> <%= GMap.header %> <%= @map.to_html %> </head><body> <%= @map.div(:width => 600, :height => 400) %> </body></html>
#You will get following output
Themocracy
Very information and easy to follow article for integrating maps in ruby on rails. I also your ‘Find latitude-longitude in rails’ article for integrating maps.
Thanks
I have a problem though, i want users to make markers on my maps. I haven’t found a solution for that through rails yet. Any suggestions ?
you have to add below code in gmap definition.
@map.event_init(@map, :click,
“function(marker,point) { if (marker) {
map.removeOverlay(marker);
} else {
map.addOverlay(new GMarker(point));
}
}”)
Let me know if you find any other problem.
i am not successful.there is error as bellow:
消息: 缺少函数 (message:lack functions)
行(row): 316
字符(char): 27
代码(code): 0
URI: http://maps.gstatic.com/intl/zh-CN_ALL/mapfiles/178b/maps2.api/main.js
消息: 对象不支持此属性或方法(message:object not support this property or method)
行: 2
字符: 1
代码: 0
URI: http://maps.gstatic.com/intl/zh-CN_ALL/mapfiles/176c/maps2.api/mod_jslinker.js
消息: 缺少对象(lack object)
行: 215
字符: 26
代码: 0
URI: http://maps.gstatic.com/intl/zh-CN_ALL/mapfiles/178b/maps2.api/main.js
Thanks a lot for the instructions. I just wanted to embed a google map in an application. Perfect solution!
Bonjour,
Thank you for your code !! Sorry but we don’t speack very good english… :/
My probleme : Your source doesn’t work for me..
I have an error about GMap (“uninitialized constant ActionController::AbstractRequest”)… I am sad because in the first post from Ptdp, it is writting “easy to follow article for integrating maps in ruby on rails”…
Thank you for your article !
Sina,
I think this rails version related issue with Google Map plugin.
try out following link,might be it will help you.
http://railsforum.com/viewtopic.php?id=24839
Thanks you for your answer.
(thanks your code)
Since the last post, our project runs
Our problem was the plugin Geokit…
see you soon!
Firstly sorry if I ask a newb question, new to ruby and programming. I am getting the following error while using your code.
ActionView::TemplateError (undefined method `to_html’ for nil:NilClass) on line #6 of app/views/homes/index.html.erb:
3:
4:
5:
6:
7:
8: 600, :height => 400) %>
9:
app/views/homes/index.html.erb:6
app/controllers/homes_controller.rb:7:in `index’
What is wrong?
Hi Bernard,
ActionView::TemplateError (undefined method `to_html’ for nil:NilClass) ,this error shows that @map variable has not assign anything.
Can you show me what you had implemented in controller part?
can’t convert Ym4r::GmPlugin::Variable to String (Ym4r::GmPlugin::Variable#to_str gives Ym4r::GmPlugin::Variable)
above is what I am getting as an error.
And, when I am adding following code in mapping.rb file of plugin,
def to_str
@variable + “;”
end
I am getting the following output instead of the map
var map; window.onload = addCodeToFunction(window.onload,function() { if (GBrowserIsCompatible()) { map = new GMap2(document.getElementById(“map_div”)); map.setCenter(new GLatLng(22.792388,79.49707),4);map.addOverlay(addInfoWindowToMarker(new GMarker(new GLatLng(22.792388,79.49707),{title : “India”}),”India”,{})); map.addOverlay(addInfoWindowToMarker(new GMarker(new GLatLng(22.792388,72.421875),{title : “Ahmedabad”}),”Ahmedabad”,{}));map.addControl(new GLargeMapControl()); map.addControl(new GMapTypeControl()); } });
I think ‘to_html’ is having some problem.
Any help is appreciated.
Reagrds
Alok Anand
Hi Alok,
Which rails version are you using? This plugin is tested up to rails 2.3.2.
Thanks
Brijesh Shah
Sir,
I am using rails 3.0.3.
Is there any new version of ym4r/gm or any other method for rails 3.0.3.
Your help is surely required and welcome.
Thanks
Alok Anand
Hi Alok,
Sorry for late reply. I was busy with some other stuff.
Following things should be done to support rails 3.
1. Add following method in class Varible under gm_plugin/mapping.rb
def to_str
@variable + “;”
end
2. user raw method for each google maps methods to avoid html contents.
Let me know if you have any problems.
Thanks
Brijesh Shah
nope….
still the same prob..
I am using Rails3 and i did all the steps to integrate gmap as you have told but i got the errors as follow….
v:* { behavior:url(#default#VML);} var map; window.onload = addCodeToFunction(window.onload,function() { if (GBrowserIsCompatible()) { map = new GMap2(document.getElementById(“map_div”)); map.setCenter(new GLatLng(22.792388,79.49707),4);map.addOverlay(addInfoWindowToMarker(new GMarker(new GLatLng(22.792388,79.49707),{title : “India”}),”India”,{})); map.addOverlay(addInfoWindowToMarker(new GMarker(new GLatLng(22.792388,72.421875),{title : “Ahmedabad”}),”Ahmedabad”,{}));map.addControl(new GLargeMapControl()); map.addControl(new GMapTypeControl()); } });
it was helpful..
Hi Alok,
Are you still getting html output on page?
Did you use raw method in code?
Thanks Brijesh… now its working fine… but may you suggest me geokit plugin which is rails 3.0 compatible.
Hi,
I’m trying to use it in Rails 3 and after modify mapping.rb and using raw method, the map is not displayed in my web, just a blank space.
Any idea?
thanks a lot!!
Hi Alberto,
What did you get page source? Also check is there any javascript error or not..
Thanks
Brijesh Shah
I got it from https://github.com/rorcraft/ym4r_gm
Hi
This plugin also works in rails 3 after modify mapping.rb and using raw method.
Did you add to_str method in Variable class? and let me know what did you get in page source (html contents)
Hi Brijesh and many thanks for your help:
I modified the mappin.rb (before this i had an to_str error)
and I’m using raw method.
Now I obtain a routing error:
DEPRECATION WARNING: ActionController::Base.relative_url_root is ineffective. Please stop using it. (called from header at ../vendor/plugins/ym4r_gm/lib/gm_plugin/map.rb:36)
ActionController::RoutingError (No route matches “/eventos/DEPRECATION%20WARNING:%20ActionController::Base.relative_url_root%20is%20ineffective.%20Please%20stop%20using%20it.%20(called%20from%20header%20at%20/…/vendor/plugins/ym4r_gm/lib/gm_plugin/map.rb:36)/javascripts/ym4r-gm.js”)
Any suggestion? I’m afraid the plugin isn’t still adapted to Rails 3 :S
I solve it! changing the relative_url_root call in the map.rb for this line:
a << "\n” unless options[:without_js]
Now I can see the map!! (but I’m afraid will be more changes to do to adapt ym4r_gm to RoR 3..)
I really appreciate your help, Brijesh. Thanks!!
Hi Alberto,
Thanks for posting this solution.
I simply forgot about this change that I did.
Thanks
Brijesh Shah
[...] already wrote a blog on how to use Google maps in rails. Earlier blog is supported in rails 2.3.x [...]
thanks for your example. but can you show me how to convert the string address enter by user , converting that address to a latitude/longitude ,and showing in the map?
Hi Ray,
I think this example helps you: http://blog.brijeshshah.com/find-latitude-longitude-in-rails/
Thanks
Brijesh Shah
thanks, it works. your blog is really helpful.
Hi Brijesh, I’m using rails 3.1.0 and I get the following error message
vendor/plugins/ym4r_gm/lib/gm_plugin/key.rb:12:in `’: uninitialized constant Ym4r::GmPlugin::ApiKey::RAILS_ROOT (NameError)
Hi Dale,
Sorry for late replay. For google maps in rails 3 try out http://blog.brijeshshah.com/google-maps-in-rails-3/
Over RAILS_ROOT is replaced with Rails.root in rails 3 version.
Thanks
Brijesh Shah