http://www.engineyard.com/blog/2011/january-contest-ride4ruby

ride4ruby.rb

require 'rubygems'
require 'nokogiri'
require 'open-uri'

class Ride4Ruby
  def find_distance_between_farthest
    farthest_west, farthest_east = find_farthest_west_and_east
    $stderr.puts "Farthest west: #{farthest_west}"
    $stderr.puts "Farthest east: #{farthest_east}"

    result = Nokogiri::XML.parse(open("http://maps.google.com/maps/api/directions/xml?origin=#{farthest_east.latitude},#{farthest_east.longitude}&destination=#{farthest_west.latitude},#{farthest_west.longitude}&sensor=false&key=#{API_KEY}"))
    result.xpath('//route/leg/distance/text').first.content
  end

  private

  Location = Struct.new(:latitude, :longitude)

  API_KEY = '#INSERT KEY HERE#'

  STATES = %w{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}

  def find_farthest_west_and_east
    find_ruby_streets if @ruby_streets.nil?
    @ruby_streets.minmax_by(&:longitude)
  end

  def find_ruby_streets
    @ruby_streets = []

    STATES.each do |state|
      result = Nokogiri::XML.parse(open("http://maps.google.com/maps/geo?q=#{state}%20Ruby%20Street&output=xml&key=#{API_KEY}"))
      result.xpath('//xmlns:Placemark').each do |placemark|
        next unless placemark.xpath('xmlns:address').first.content =~ /USA$/

        points = placemark.xpath('xmlns:Point/xmlns:coordinates').first.content.split(',')

        # Create Location object
        @ruby_streets.push Location.new(points[1].to_f, points[0].to_f)
      end
    end
  end
end

ride4ruby = Ride4Ruby.new
puts ride4ruby.find_distance_between_farthest