gistfile1.rb

require 'net/http'
require 'rexml/document'
require 'CGI'

Location = Struct.new(:longitude, :latitude, :state, :country, :city, :zip_code)
Location.class_eval do
  def self.from_placemark_and_state(placemark, state)
    longitude, latitude = placemark.elements['Point/coordinates'].text.split(',').map(&:to_f)

    location = Location.new(longitude, latitude, state)

    paths = %w(AddressDetails/Country/CountryNameCode AddressDetails/Country/AdministrativeArea/SubAdministrativeArea/Locality/LocalityName AddressDetails/Country/AdministrativeArea/SubAdministrativeArea/Locality/PostalCode/PostalCodeNumber)
    location.country, location.city, location.zip_code = paths.map do |path|
      result = placemark.elements[path]
      result != nil ? result.text : nil
    end
    location
  end

  def to_s
    members.map { |member| "#{member.to_s}=\"#{self[member]}\"" }.join(' ')
  end
end

def get_extreme_locations(states, maps_key)
  western_location = Location.new(180.0)
  eastern_location = Location.new(-180.0)

  states.each do |state|
    url = "http://maps.google.com/maps/geo?q=#{CGI.escape(state)}%20Ruby%20Street&output=xml&key=#{maps_key}"
    doc = REXML::Document.new(Net::HTTP.get_response(URI.parse(url)).body)

    doc.elements.each('kml/Response/Placemark') do |placemark|
      location = Location.from_placemark_and_state(placemark, state)

      next unless location.country == "US"

      western_location = location if western_location.longitude > location.longitude
      eastern_location = location if eastern_location.longitude < location.longitude
    end
  end
  [ eastern_location, western_location ]
end

def driving_distance_between_locations(location1, location2, maps_key)
  # The following url returns the driving directions, it would be better to get the cycling distance or to calculate the straigth-line distance
  url = "http://maps.google.com/maps/api/directions/xml?origin=#{location1.latitude},#{location1.longitude}&destination=#{location2.latitude},#{location2.longitude}&sensor=false&key=#{maps_key}"
  doc = REXML::Document.new(Net::HTTP.get_response(URI.parse(url)).body)

  doc.elements["DirectionsResponse/route/leg/distance/text"].text
end

states = ['Alabama', 'Alaska', 'Arizona', 'Arkansas', 'California', 'Colorado', 'Connecticut', 'Delaware', 'District of Columbia', 'Florida', 'Georgia', 'Idaho', 'Illinois', 'Indiana', 'Iowa', 'Kansas', 'Kentucky', 'Louisiana', 'Maine', 'Maryland', 'Massachusetts', 'Michigan', 'Minnesota', 'Mississippi', 'Missouri', 'Montana', 'Nebraska', 'Nevada', 'New Hampshire', 'New Jersey', 'New Mexico', 'New York', 'North Carolina', 'North Dakota', 'Ohio', 'Oklahoma', 'Oregon', 'Pennsylvania', 'Rhode Island', 'South Carolina', 'South Dakota', 'Tennessee', 'Texas', 'Utah', 'Vermont', 'Virginia', 'Washington', 'West Virginia', 'Wisconsin', 'Wyoming']
maps_key = 'insert your key here'

eastern_location, western_location = get_extreme_locations(states, maps_key)
puts "Eastern location's data: #{eastern_location.to_s}"
puts "Western location's data: #{western_location.to_s}"
puts "Distance: #{driving_distance_between_locations(eastern_location, western_location, maps_key)}"