Working With Rails

Acts As Geocodable

= acts_as_geocodable

acts_as_geocodable is a plugin to help build geo-aware applications. It automatically geocodes your models when they are saved, giving you the ability to search by location and calculate distances between records.

Usage

event = Event.create :street => "777 NE Martin Luther King, Jr. Blvd.",
  :locality => "Portland", :region => "Oregon", :postal_code => 97232

event.geocode.latitude                                #=> 45.529100000000
event.geocode.longitude                               #=> -122.644200000000

event.distance_to "49423"                             #=> 1807.66560483205

Event.find(:all, :within => 50, :origin => "97232")

Event.find(:nearest, :origin => "Portland, OR")

Upgrading

If you’re upgrading from a previous version of this plugin, note that :city has been renamed to :locality to be consistent with Graticule 0.2. Create a migration that has:

rename_column :geocodes, :city, :locality

Also remember to change your mapping in your geocodable classes to use the :locality key instead of :city:

class Event < ActiveRecord::Base acts_as_geocodable :address => {:street => :address1, :locality => :city, :region => :state, :postal_code => :zip} end

Installation

Graticule[link:http://rubyforge.org/projects/graticule] is used for all the heavy lifting.

gem install graticule --include-dependencies

Install the plugin

script/plugin install -x http://source.collectiveidea.com/public/rails/plugins/acts_as_geocodable/

Configuration

Create the required tables

script/generate geocodable_migration add_geocodable_tables
rake db:migrate

Set the default geocoder in your environment.rb file.

Geocode.geocoder = Graticule.service(:yahoo).new 'your_api_key'

Then, in each model you want to make geocodable, add acts_as_geocodable.

class Event < ActiveRecord::Base
    acts_as_geocodable
end

The only requirement is that your model must have address fields. By default, acts_as_geocodable looks for attributes called street, locality, region, postal_code, and country. To change these, you can provide a mapping in the :address option:

class Event < ActiveRecord::Base
    acts_as_geocodable :address => {:street => :address1, :locality => :city, :region => :state, :postal_code => :zip}
end

If that doesn’t meet your needs, simply override the default to_location method in your model, and return a Graticule::Location with those attributes set.

acts_as_geocodable can also update your address fields with the data returned from the geocoding service:

class Event < ActiveRecord::Base
    acts_as_geocodable :normalize_address => true
end

== IP-based Geocoding

acts_as_geocodable adds a remote_location method in your controllers that uses http://hostip.info to guess remote users location based on their IP address.

def index
  @nearest = Store.find(:nearest, :origin => remote_location) if remote_location
  @stores = Store.find(:all)
end

Keep in mind that IP-based geocoding is not always accurate, and often will not return any results.

Development

The source code is available at:

http://source.collectiveidea.com/public/rails/plugins/acts_as_geocodable/

Patches and suggestions are welcome!

To Do

• Documentation!!!
• configurable formulas

NOTE: This description has been extracted from the Plugin README and so the formatting may need updating to make browser friendly