README.md

Geocoder

Geocoder is a complete geocoding solution for Ruby. With Rails it adds geocoding (by street or IP address), reverse geocoding (finding street address based on given coordinates), and distance queries. It's as simple as calling geocode on your objects, and then using a scope like Venue.near("Billings, MT").

Please note that this README is for the current HEAD and may document features not present in the latest gem release. For this reason, you may want to instead view the README for your particular version.

Compatibility

• Supports multiple Ruby versions: Ruby 1.9.3, 2.0.x, 2.1.x, JRuby, and Rubinius.
• Supports multiple databases: MySQL, PostgreSQL, SQLite, and MongoDB (1.7.0 and higher).
• Supports Rails 3 and 4. If you need to use it with Rails 2 please see the rails2 branch (no longer maintained, limited feature set).
• Works very well outside of Rails, you just need to install either the json (for MRI) or json_pure (for JRuby) gem.

Rails 4.1 Note

Due to a change in ActiveRecord's count method you will need to use count(:all) to explicitly count all columns ("*") when using a near scope. Using near and calling count with no argument will cause exceptions in many cases.

Installation

Install Geocoder like any other Ruby gem:

gem install geocoder

Or, if you're using Rails/Bundler, add this to your Gemfile:

gem 'geocoder'

and run at the command prompt:

bundle install

Object Geocoding

ActiveRecord

Your model must have two attributes (database columns) for storing latitude and longitude coordinates. By default they should be called latitude and longitude but this can be changed (see "Model Configuration" below):

rails generate migration AddLatitudeAndLongitudeToModel latitude:float longitude:float
rake db:migrate

For reverse geocoding your model must provide a method that returns an address. This can be a single attribute, but it can also be a method that returns a string assembled from different attributes (eg: city, state, and country).

Next, your model must tell Geocoder which method returns your object's geocodable address:

geocoded_by :full_street_address   # can also be an IP address
after_validation :geocode          # auto-fetch coordinates

For reverse geocoding, tell Geocoder which attributes store latitude and longitude:

reverse_geocoded_by :latitude, :longitude
after_validation :reverse_geocode  # auto-fetch address

Mongoid

First, your model must have an array field for storing coordinates:

field :coordinates, :type => Array

You may also want an address field, like this:

field :address

but if you store address components (city, state, country, etc) in separate fields you can instead define a method called address that combines them into a single string which will be used to query the geocoding service.

Once your fields are defined, include the Geocoder::Model::Mongoid module and then call geocoded_by:

include Geocoder::Model::Mongoid
geocoded_by :address               # can also be an IP address
after_validation :geocode          # auto-fetch coordinates

Reverse geocoding is similar:

include Geocoder::Model::Mongoid
reverse_geocoded_by :coordinates
after_validation :reverse_geocode  # auto-fetch address

Once you've set up your model you'll need to create the necessary spatial indices in your database:

rake db:mongoid:create_indexes

Be sure to read Latitude/Longitude Order in the Notes on MongoDB section below on how to properly retrieve latitude/longitude coordinates from your objects.

MongoMapper

MongoMapper is very similar to Mongoid, just be sure to include Geocoder::Model::MongoMapper.

Mongo Indices

By default, the methods geocoded_by and reverse_geocoded_by create a geospatial index. You can avoid index creation with the :skip_index option, for example:

include Geocoder::Model::Mongoid
geocoded_by :address, :skip_index => true

Bulk Geocoding

If you have just added geocoding to an existing application with a lot of objects you can use this Rake task to geocode them all:

rake geocode:all CLASS=YourModel

Geocoder will print warnings if you exceed the rate limit for your geocoding service. Some services — Google notably — enforce a per-second limit in addition to a per-day limit. To avoid exceeding the per-second limit, you can add a SLEEP option to pause between requests for a given amount of time. You can also load objects in batches to save memory, for example:

rake geocode:all CLASS=YourModel SLEEP=0.25 BATCH=100

Avoiding Unnecessary API Requests

Geocoding only needs to be performed under certain conditions. To avoid unnecessary work (and quota usage) you will probably want to geocode an object only when:

• an address is present
• the address has been changed since last save (or it has never been saved)

The exact code will vary depending on the method you use for your geocodable string, but it would be something like this:

after_validation :geocode, if: ->(obj){ obj.address.present? and obj.address_changed? }

Request Geocoding by IP Address

Geocoder adds location and safe_location methods to the standard Rack::Request object so you can easily look up the location of any HTTP request by IP address. For example, in a Rails controller or a Sinatra app:

# returns Geocoder::Result object
result = request.location

The location method is vulnerable to trivial IP address spoofing via HTTP headers. If that's a problem for your application, use safe_location instead, but be aware that safe_location will not try to trace a request's originating IP through proxy headers; you will instead get the location of the last proxy the request passed through, if any (excepting any proxies you have explicitly whitelisted in your Rack config).

Note that these methods will usually return nil in your test and development environments because things like "localhost" and "0.0.0.0" are not an Internet IP addresses.

See Advanced Geocoding below for more information about Geocoder::Result objects.

Location-Aware Database Queries

To find objects by location, use the following scopes:

Venue.near('Omaha, NE, US', 20)    # venues within 20 miles of Omaha
Venue.near([40.71, -100.23], 20)    # venues within 20 miles of a point
Venue.near([40.71, -100.23], 20, :units => :km)
                                   # venues within 20 kilometres of a point
Venue.geocoded                     # venues with coordinates
Venue.not_geocoded                 # venues without coordinates

With geocoded objects you can do things like this:

if obj.geocoded?
  obj.nearbys(30)                      # other objects within 30 miles
  obj.distance_from([40.714,-100.234]) # distance from arbitrary point to object
  obj.bearing_to("Paris, France")      # direction from object to arbitrary point
end

Some utility methods are also available:

# look up coordinates of some location (like searching Google Maps)
Geocoder.coordinates("25 Main St, Cooperstown, NY")
 => [42.700149, -74.922767]

# distance (in miles) between Eiffel Tower and Empire State Building
Geocoder::Calculations.distance_between([47.858205,2.294359], [40.748433,-73.985655])
 => 3619.77359999382

# find the geographic center (aka center of gravity) of objects or points
Geocoder::Calculations.geographic_center([city1, city2, [40.22,-73.99], city4])
 => [35.14968, -90.048929]

Please see the code for more methods and detailed information about arguments (eg, working with kilometers).

Distance and Bearing

When you run a location-aware query the returned objects have two attributes added to them (only w/ ActiveRecord):

• obj.distance - number of miles from the search point to this object
• obj.bearing - direction from the search point to this object

Results are automatically sorted by distance from the search point, closest to farthest. Bearing is given as a number of clockwise degrees from due north, for example:

• 0 - due north
• 180 - due south
• 90 - due east
• 270 - due west
• 230.1 - southwest
• 359.9 - almost due north

You can convert these numbers to compass point names by using the utility method provided:

Geocoder::Calculations.compass_point(355) # => "N"
Geocoder::Calculations.compass_point(45)  # => "NE"
Geocoder::Calculations.compass_point(208) # => "SW"

Note: when using SQLite distance and bearing values are provided for interface consistency only. They are not very accurate.

To calculate accurate distance and bearing with SQLite or MongoDB:

obj.distance_to([43.9,-98.6])  # distance from obj to point
obj.bearing_to([43.9,-98.6])   # bearing from obj to point
obj.bearing_from(obj2)         # bearing from obj2 to obj

The bearing_from/to methods take a single argument which can be: a [lat,lon] array, a geocoded object, or a geocodable address (string). The distance_from/to methods also take a units argument (:mi, :km, or :nm for nautical miles).

Model Configuration

You are not stuck with using the latitude and longitude database column names (with ActiveRecord) or the coordinates array (Mongo) for storing coordinates. For example:

geocoded_by :address, :latitude  => :lat, :longitude => :lon # ActiveRecord
geocoded_by :address, :coordinates => :coords                # MongoDB

This means you can geocode multiple addresses as well:

geocoded_by :start_address, latitude: :start_latitude, longitude: :start_longitude
geocoded_by :end_address, latitude: :end_latitude, longitude: :end_longitude

The address method can return any string you'd use to search Google Maps. For example, any of the following are acceptable:

• "714 Green St, Big Town, MO"
• "Eiffel Tower, Paris, FR"
• "Paris, TX, US"

If your model has street, city, state, and country attributes you might do something like this:

geocoded_by :address

def address
  [street, city, state, country].compact.join(', ')
end

For reverse geocoding you can also specify an alternate name attribute where the address will be stored, for example:

reverse_geocoded_by :latitude, :longitude, :address => :location  # ActiveRecord
reverse_geocoded_by :coordinates, :address => :loc                # MongoDB

You can also configure a specific lookup for your model which will override the globally-configured lookup, for example:

geocoded_by :address, :lookup => :yandex

You can also specify a proc if you want to choose a lookup based on a specific property of an object, for example you can use specialized lookups for different regions:

geocoded_by :address, :lookup => lambda{ |obj| obj.geocoder_lookup }

def geocoder_lookup
  if country_code == "RU"
    :yandex
  elsif country_code == "CN"
    :baidu
  else
    :google
  end
end

Advanced Querying

When querying for objects (if you're using ActiveRecord) you can also look within a square rather than a radius (circle) by using the within_bounding_box scope:

distance = 20
center_point = [40.71, 100.23]
box = Geocoder::Calculations.bounding_box(center_point, distance)
Venue.within_bounding_box(box)

This can also dramatically improve query performance, especially when used in conjunction with indexes on the latitude/longitude columns. Note, however, that returned results do not include distance and bearing attributes. Note that #near performs both bounding box and radius queries for speed.

You can also specify a minimum radius (if you're using ActiveRecord and not Sqlite) to constrain the lower bound (ie. think of a donut, or ring) by using the :min_radius option:

box = Geocoder::Calculations.bounding_box(center_point, distance, :min_radius => 10.5)

With ActiveRecord, you can specify alternate latitude and longitude column names for a geocoded model (useful if you store multiple sets of coordinates for each object):

Venue.near("Paris", 50, latitude: :secondary_latitude, longitude: :secondary_longitude)

Advanced Geocoding

So far we have looked at shortcuts for assigning geocoding results to object attributes. However, if you need to do something fancy you can skip the auto-assignment by providing a block (takes the object to be geocoded and an array of Geocoder::Result objects) in which you handle the parsed geocoding result any way you like, for example:

reverse_geocoded_by :latitude, :longitude do |obj,results|
  if geo = results.first
    obj.city    = geo.city
    obj.zipcode = geo.postal_code
    obj.country = geo.country_code
  end
end
after_validation :reverse_geocode

Every Geocoder::Result object, result, provides the following data:

• result.latitude - float
• result.longitude - float
• result.coordinates - array of the above two
• result.address - string
• result.city - string
• result.state - string
• result.state_code - string
• result.postal_code - string
• result.country - string
• result.country_code - string

If you're familiar with the results returned by the geocoding service you're using you can access even more data (call the #data method of any Geocoder::Result object to get the full parsed response), but you'll need to be familiar with the particular Geocoder::Result object you're using and the structure of your geocoding service's responses. (See below for links to geocoding service documentation.)

Geocoding Service ("Lookup") Configuration

Geocoder supports a variety of street and IP address geocoding services. The default lookups are :google for street addresses and :freegeoip for IP addresses. Please see the listing and comparison below for details on specific geocoding services (not all settings are supported by all services).

To create a Rails initializer with an example configuration:

rails generate geocoder:config

Some common configuration options are:

# config/initializers/geocoder.rb
Geocoder.configure(

  # geocoding service (see below for supported options):
  :lookup => :yandex,

  # IP address geocoding service (see below for supported options):
  :ip_lookup => :maxmind,

  # to use an API key:
  :api_key => "...",

  # geocoding service request timeout, in seconds (default 3):
  :timeout => 5,

  # set default units to kilometers:
  :units => :km,

  # caching (see below for details):
  :cache => Redis.new,
  :cache_prefix => "..."

)

Please see lib/geocoder/configuration.rb for a complete list of configuration options. Additionally, some lookups have their own configuration options, some of which are directly supported by Geocoder. For example, to specify a value for Google's bounds parameter:

# with Google:
Geocoder.search("Paris", :bounds => [[32.1,-95.9], [33.9,-94.3]])

Please see the source code for each lookup to learn about directly supported parameters. Parameters which are not directly supported can be specified using the :params option, by which you can pass arbitrary parameters to any geocoding service. For example, to use Nominatim's countrycodes parameter:

# with Nominatim:
Geocoder.search("Paris", :params => {:countrycodes => "gb,de,fr,es,us"})

You can also configure multiple geocoding services at once, like this:

Geocoder.configure(

  :timeout => 2,
  :cache => Redis.new,

  :yandex => {
    :api_key => "...",
    :timeout => 5
  },

  :baidu => {
    :api_key => "..."
  },

  :maxmind => {
    :api_key => "...",
    :service => :omni
  }

)

The above combines global and service-specific options and could be useful if you specify different geocoding services for different models or under different conditions. Lookup-specific settings override global settings so, for example, in the above the timeout for all lookups would be 2 seconds, except for Yandex which would be 5.

Street Address Services

The following is a comparison of the supported geocoding APIs. The "Limitations" listed for each are a very brief and incomplete summary of some special limitations beyond basic data source attribution. Please read the official Terms of Service for a service before using it.

Google (:google, :google_premier)

• API key: required for Premier, optional for the free service (if using the free service with API key, https is required. Add :use_https => true to Geocoder.configure)
• Key signup: https://developers.google.com/maps/documentation/business/
• Quota: 2,500 requests/day, 100,000 with Google Maps API Premier
• Region: world
• SSL support: yes
• Languages: ar, eu, bg, bn, ca, cs, da, de, el, en, en-AU, en-GB, es, eu, fa, fi, fil, fr, gl, gu, hi, hr, hu, id, it, iw, ja, kn, ko, lt, lv, ml, mr, nl, no, pl, pt, pt-BR, pt-PT, ro, ru, sk, sl, sr, sv, tl, ta, te, th, tr, uk, vi, zh-CN, zh-TW (see http://spreadsheets.google.com/pub?key=p9pdwsai2hDMsLkXsoM05KQ&gid=1)
• Extra options: :bounds - pass SW and NE coordinates as an array of two arrays to bias results towards a viewport
• Documentation: http://code.google.com/apis/maps/documentation/geocoding/#JSON
• Terms of Service: http://code.google.com/apis/maps/terms.html#section_10_12
• Limitations: "You must not use or display the Content without a corresponding Google map, unless you are explicitly permitted to do so in the Maps APIs Documentation, or through written permission from Google." "You must not pre-fetch, cache, or store any Content, except that you may store: (i) limited amounts of Content for the purpose of improving the performance of your Maps API Implementation..."
• Notes: To use Google Premier set Geocoder.configure(:lookup => :google_premier, :api_key => [key, client, channel]).

Google Places Details (:google_places_details)

The Google Places Details API is not, strictly speaking, a geocoding service. It accepts a Google place_id and returns address information, ratings and reviews. A place_id can be obtained from the Google Places Autocomplete API and should be passed to Geocoder as the first search argument: Geocoder.search("ChIJhRwB-yFawokR5Phil-QQ3zM", :lookup => :google_places_details).

• API key: required
• Key signup: https://code.google.com/apis/console/
• Quota: 1,000 request/day, 100,000 after credit card authentication
• Region: world
• SSL support: yes
• Languages: ar, eu, bg, bn, ca, cs, da, de, el, en, en-AU, en-GB, es, eu, fa, fi, fil, fr, gl, gu, hi, hr, hu, id, it, iw, ja, kn, ko, lt, lv, ml, mr, nl, no, pl, pt, pt-BR, pt-PT, ro, ru, sk, sl, sr, sv, tl, ta, te, th, tr, uk, vi, zh-CN, zh-TW (see http://spreadsheets.google.com/pub?key=p9pdwsai2hDMsLkXsoM05KQ&gid=1)
• Documentation: https://developers.google.com/places/documentation/details
• Terms of Service: https://developers.google.com/places/policies
• Limitations: "If your application displays Places API data on a page or view that does not also display a Google Map, you must show a "Powered by Google" logo with that data."

Yahoo BOSS (:yahoo)

• API key: requires OAuth consumer key and secret (set Geocoder.configure(:api_key => [key, secret]))
• Key signup: http://developer.yahoo.com/boss/geo/
• Quota: unlimited, but subject to usage fees
• Region: world
• SSL support: no
• Languages: en, fr, de, it, es, pt, nl, zh, ja, ko
• Documentation: http://developer.yahoo.com/boss/geo/docs/index.html
• Terms of Service: http://info.yahoo.com/legal/us/yahoo/boss/tou/?pir=ucJPcJ1ibUn.h.d.lVmlcbcEkoHjwJ_PvxG9SLK9VIbIQAw1XFrnDqY-
• Limitations: No mass downloads, no commercial map production based on the data, no storage of data except for caching.

Bing (:bing)

• API key: required (set Geocoder.configure(:lookup => :bing, :api_key => key))
• Key signup: http://www.bingmapsportal.com
• Quota: 50,000 requests/24 hrs
• Region: world
• SSL support: no
• Languages: ?
• Documentation: http://msdn.microsoft.com/en-us/library/ff701715.aspx
• Terms of Service: http://www.microsoft.com/maps/product/terms.html
• Limitations: No country codes or state names. Must be used on "public-facing, non-password protected web sites," "in conjunction with Bing Maps or an application that integrates Bing Maps."

Nominatim (:nominatim)

• API key: none
• Quota: 1 request/second
• Region: world
• SSL support: no
• Languages: ?
• Documentation: http://wiki.openstreetmap.org/wiki/Nominatim
• Terms of Service: http://wiki.openstreetmap.org/wiki/Nominatim_usage_policy
• Limitations: Please limit request rate to 1 per second and include your contact information in User-Agent headers (eg: Geocoder.configure(:http_headers => { "User-Agent" => "your contact info" })). Data licensed under CC-BY-SA (you must provide attribution).

OpenCageData (:opencagedata)

• API key: required
• Key signup: http://geocoder.opencagedata.com
• Quota: 2500 requests / day, then ability to purchase more (free during beta)
• Region: world
• SSL support: yes
• Languages: worldwide
• Documentation: http://geocoder.opencagedata.com/api.html
• Limitations: Data licensed under CC-BY-SA or (you must provide attribution).

Yandex (:yandex)

• API key: none
• Quota: 25000 requests / day
• Region: world
• SSL support: no
• Languages: Russian, Belarusian, Ukrainian, English, Turkish (only for maps of Turkey)
• Documentation: http://api.yandex.com.tr/maps/doc/intro/concepts/intro.xml
• Terms of Service: http://api.yandex.com.tr/maps/doc/intro/concepts/intro.xml#rules
• Limitations: ?

Geocoder.ca (:geocoder_ca)

• API key: none
• Quota: ?
• Region: US and Canada
• SSL support: no
• Languages: English
• Documentation: ?
• Terms of Service: http://geocoder.ca/?terms=1
• Limitations: "Under no circumstances can our data be re-distributed or re-sold by anyone to other parties without our written permission."

Geocoder.us (:geocoder_us)

• API key: HTTP Basic Auth
• Sign up: http://geocoder.us/user/signup
• Quota: You can purchase 20,000 credits at a time for $50
• Region: US
• SSL support: no
• Languages: English
• Documentation: http://geocoder.us/help/
• Terms of Service: http://geocoder.us/terms.shtml
• Limitations: ?

Mapquest (:mapquest)