Encode polyline

encode.rb

def encode(points, precision = 1e5)
 result = ""
 last_lat = last_lng = last_timestamp = 0
 # Convert each point (lat, lng, ts) to a string
 points.each do |point|
  # Convert to integer
  lat = (point[0] * precision).round
  lng = (point[1] * precision).round
  timestamp = point[2]
  # Compute the difference with the previous point
  diff_lat = lat - last_lat
  diff_lng = lng - last_lng
  diff_timestamp = timestamp - last_timestamp
  # See fast-polyline github repository for encode_number
  chunks_lat = encode_number(diff_lat)
  chunks_lng = encode_number(diff_lng)
  chunks_ts = encode_number(diff_timestamp)
  # Glue the strings together
  result << chunks_lat << chunks_lng << chunks_ts
  # Save the current point for computing the differences later
  last_lat = lat
  last_lng = lng
  last_timestamp = timestamp
 end
 # The encoded string:
 result
end