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Geocoder adds database-agnostic object geocoding to Rails (via Google). It does not rely on proprietary database functions so reasonably accurate distances can be calculated in MySQL or even SQLite.
script/plugin install git://github.com/alexreisner/geocoder.git
or *as a gem*:
# add to config/environment.rb:
config.gem :geocoder, :source => "http://gemcutter.org/"
# at command prompt:
sudo rake gems:install
To add geocoding features to a class:
Alex Reisner
committed
geocoded_by :location
Be sure your class defines attributes for storing latitude and longitude (use +float+ or +double+ database columns) and a location (human-readable address to be geocoded). These attribute names are all configurable; for example, to use +address+, +lat+, and +lon+ respectively:
geocoded_by :address, :latitude => :lat, :longitude => :lon
A geocodable string is anything you'd use to search Google Maps. Any of the following are acceptable:
Eiffel Tower, Paris, FR
Paris, TX, US
Alex Reisner
committed
If your model has +address+, +city+, +state+, and +country+ attributes your +location+ method might look something like this:
def location
[address, city, state, country].compact.join(', ')
end
== Features
Assuming +Venue+ is a geocoded model:
Venue.find_near('Omaha, NE, US', 20) # venues within 20 miles of Omaha
Venue.find_near([40.71, 100.23], 20) # venues within 20 miles of a point
Venue.geocoded # venues with coordinates
Venue.not_geocoded # venues without coordinates
Assuming +obj+ has a valid string for its +location+:
obj.fetch_coordinates # returns coordinates [lat, lon]
obj.fetch_coordinates! # also writes coordinates to object
Assuming +obj+ is geocoded (has latitude and longitude):
obj.nearbys(30) # other objects within 30 miles
obj.distance_to(40.714, -100.234) # distance to arbitrary point
Some utility methods are also available:
# distance (in miles) between Eiffel Tower and Empire State Building
Geocoder.distance_between( 48.858205,2.294359, 40.748433,-73.985655 )
# look up coordinates of some location (like searching Google Maps)
Geocoder.fetch_coordinates("25 Main St, Cooperstown, NY")
Please see the code for more methods and detailed information about arguments (eg, working with kilometers).
Copyright (c) 2009 Alex Reisner, released under the MIT license