Ruby Geocoding Tutorial

Install the Ruby gem

gem install opencage-geocoder

Or in your Gemfile:

source 'https://rubygems.org'
gem 'opencage-geocoder'

Convert latitude, longitude to an address

require 'opencage/geocoder'

geocoder = OpenCage::Geocoder.new(api_key: 'YOUR-API-KEY')

result = geocoder.reverse_geocode(51.5019951, -0.0698806)
p result.address
# output is 'Reeds Wharf, 33 Mill Street, London SE15, United Kingdom'

Geocode an address or place name

results = geocoder.geocode('82 Clerkenwell Road, London')
p results.first.coordinates
# [ 51.5221558691, -0.100838524406 ]

results = geocoder.geocode('Manchester')
results.each { |res| p res.address }
# "Manchester, Greater Manchester, England, United Kingdom"
# "Manchester, NH, United States of America"
# "Manchester, Jamaica"
# "Manchester, CT 06042, United States of America"
# ...

# We want the city in Canada and results in Japanease
results = geocoder.geocode('Manchester', country_code: 'CA', language: 'ja')
p results.first.address
# "Manchester, ノバスコシア州, カナダ"
p results.first.components
# {
#   "_type" => "city",
#   "city" => "Manchester",
#   "county" => "Guysborough County",
#   "state" => "ノバスコシア州",
#   "state_code" => "NS",
#   "country" => "カナダ",
#   "country_code" => "ca",
#   "ISO_3166-1_alpha-2" => "CA",
#   "ISO_3166-1_alpha-3" => "CAN"
# }

Bulk-geocode places

Note: this example geocodes each coordinate pair in a file in series.

On Github we also have an example where we show how to geocode in parallel using Ruby.

Fill a text file queries.txt with queries:

24.77701,121.02189
31.79261,35.21785
9.54828,44.07715
59.92903,30.32989

Then loop through the file:

results = []
File.foreach('queries.txt') do |line|
  lat, lng = line.chomp.split(',')

  # Use Float() rather than #to_f because it will throw an ArgumentError if
  # there is an invalid line in the queries.txt file
  result = geocoder.reverse_geocode(Float(lat), Float(lng))
  results.push(result)
rescue ArgumentError, OpenCage::Geocoder::GeocodingError => error
  # Stop looping through the queries if there is an error
  puts 'Error: ' + error.message
  break
end

results.each do |r|
  p r.address)
end
# 韓國館, 金山十一街, 金山里, Hsinchu 30082, Taiwan
# David Hazan 11, NO Jerusalem, Israel
# هرجيسا, Jameeco Weyn, Hargeisa, Somalia
# Китайское бистро, Apraksin Yard, Михайловский проезд ...

gem install geocoder

source 'https://rubygems.org'
gem 'geocoder'

#!/usr/bin/env ruby

require 'geocoder'

Geocoder.configure(lookup: :opencagedata, api_key: "YOUR-API-KEY")

results = Geocoder.search("57 Erb Street West Waterloo, ON, Canada N2L 6C2")

result = results.first

puts "#{result.latitude}, #{result.longitude}"   
# output is 43.463796, -80.52608

#!/usr/bin/env ruby

require 'geocoder'

Geocoder.configure(lookup: :opencagedata, api_key: "YOUR-API-KEY")

results = Geocoder.search([43.463796, -80.52608], reverse_geocode: true)

result = results.first

puts result.address
# output is "63 Erb Street West, Waterloo, ON N2L 1V4, Canada"

gem install geokit

source 'https://rubygems.org'
gem 'geokit'

require 'geokit'

Geokit::Geocoders::OpencageGeocoder.key = 'YOUR-API-KEY'

Geokit::Geocoders::provider_order = [:opencage]

result = Geokit::Geocoders::MultiGeocoder.geocode("51.2157153, 1.3903743")

puts "#{result.provider}: #{result.full_address}"
# Output is "opencage: Mill Road, South East, Kent, England, CT14 9BD, GB"

#!/usr/bin/env ruby

require 'geokit'

Geokit::Geocoders::OpencageGeocoder.key = 'YOUR-API-KEY'

Geokit::Geocoders::provider_order = [:opencage]

result = Geokit::Geocoders::MultiGeocoder.geocode("900 Sycamore Drive")

puts "#{result.provider}: #{result.latitude}, #{result.longitude}"