def contains? y, x
    y = y.to_f if y.is_a?(String)
    x = x.to_f if x.is_a?(String)
    lats = coordinates.collect{|c| c[0].to_f}
    longs = coordinates.collect{|c| c[1].to_f}
    within = false
    j = lats.size - 1
    lats.each_with_index do |lat,i|
      long = longs[i]
      next_lat = lats[j]
      next_long = longs[j]
      if ( (lat <= y) && (y < next_lat) ) || ( (next_lat <= y) && (y < lat) )
        if( (next_long - long) * (y-lat) / (next_lat - lat) + long ) > x
          within = !within
        end
      end
      j = i
    end
    within
  end