Module: TimeAwarePolyline

Defined in:
lib/time_aware_polyline.rb

Constant Summary collapse

GPX_TIME_FORMAT =

2016-07-21T05:43:09+00:00

"%FT%T%:z".freeze

Class Method Summary collapse

Class Method Details

._add_value_to_polyline(value, polyline) ⇒ Object 



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# File 'lib/time_aware_polyline.rb', line 82

def self._add_value_to_polyline(value, polyline)
  value = value.negative? ? ~(value << 1) : value << 1
  while value >= 32
    polyline << ((32 | (value & 31)) + 63).chr
    value >>= 5
  end
  polyline << (value + 63).chr
  polyline
end

._decode_lat_lng_time_from_polyline(polyline, index) ⇒ Object 



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# File 'lib/time_aware_polyline.rb', line 92

def self._decode_lat_lng_time_from_polyline(polyline, index)
  index, latitude_part = _get_decoded_dimension_from_polyline(polyline, index)
  index, longitude_part = _get_decoded_dimension_from_polyline(polyline, index)
  index, time_part = _get_decoded_dimension_from_polyline(polyline, index)
  [index, latitude_part, longitude_part, time_part]
end

._extend_time_aware_polyline(polyline: "", gpx_logs: nil, last_gpx_log: nil) ⇒ Object 



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# File 'lib/time_aware_polyline.rb', line 50

def self._extend_time_aware_polyline(polyline: "", gpx_logs: nil, last_gpx_log: nil)
  if last_gpx_log.nil?
    last_latitude = 0
    last_longitude = 0
    last_time = 0
  else
    last_latitude, last_longitude, last_time = _get_gpx_for_polyline(last_gpx_log)
  end
  if polyline.nil?
    polyline = ""
  end
  if gpx_logs.nil?
    return polyline
  end

  gpx_logs.each do |gpx_log|
    latitude, longitude, time_stamp = _get_gpx_for_polyline(gpx_log)
    delta_latitude = latitude - last_latitude
    delta_longitude = longitude - last_longitude
    delta_time = time_stamp - last_time

    _add_value_to_polyline(delta_latitude, polyline)
    _add_value_to_polyline(delta_longitude, polyline)
    _add_value_to_polyline(delta_time, polyline)

    last_latitude = latitude
    last_longitude = longitude
    last_time = time_stamp
  end
  polyline
end

._get_coordinate_for_polyline(coordinate) ⇒ Object 



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# File 'lib/time_aware_polyline.rb', line 34

def self._get_coordinate_for_polyline(coordinate)
  (coordinate * 100_000.0).round(0).to_i
end

._get_coordinate_from_polyline(int_representation) ⇒ Object 



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# File 'lib/time_aware_polyline.rb', line 38

def self._get_coordinate_from_polyline(int_representation)
  (int_representation * 1e-05).round(5)
end

._get_decoded_dimension_from_polyline(polyline, index) ⇒ Object 



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# File 'lib/time_aware_polyline.rb', line 99

def self._get_decoded_dimension_from_polyline(polyline, index)
  result = 1
  shift = 0
  b = nil
  while b.nil? || b >= 31
    b = (polyline[index].ord - 63) - 1
    index += 1
    result += b << shift
    shift += 5
  end
  result = (result & 1).zero? ? result : ~result
  [index, result >> 1]
end

._get_gpx_for_polyline(gpx) ⇒ Object 



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# File 'lib/time_aware_polyline.rb', line 42

def self._get_gpx_for_polyline(gpx)
  [_get_coordinate_for_polyline(gpx[0]), _get_coordinate_for_polyline(gpx[1]), _get_time_for_polyline(gpx[2])]
end

._get_gpx_from_decoded(lat_rep, lon_rep, time_stamp_rep) ⇒ Object 



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# File 'lib/time_aware_polyline.rb', line 46

def self._get_gpx_from_decoded(lat_rep, lon_rep, time_stamp_rep)
  [_get_coordinate_from_polyline(lat_rep), _get_coordinate_from_polyline(lon_rep), _get_time_from_polyline(time_stamp_rep)]
end

._get_time_for_polyline(iso_time) ⇒ Object 



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# File 'lib/time_aware_polyline.rb', line 26

def self._get_time_for_polyline(iso_time)
  Time.parse(iso_time).to_i
end

._get_time_from_polyline(int_representation) ⇒ Object 



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# File 'lib/time_aware_polyline.rb', line 30

def self._get_time_from_polyline(int_representation)
  Time.at(int_representation).utc.strftime(GPX_TIME_FORMAT)
end

.decode_time_aware_polyline(polyline) ⇒ Object 



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# File 'lib/time_aware_polyline.rb', line 9

def self.decode_time_aware_polyline(polyline)
  gpx_logs = []
  index = 0
  latitude = 0
  longitude = 0
  time_stamp = 0
  while index < polyline.size
    index, latitude_part, longitude_part, time_part = _decode_lat_lng_time_from_polyline(polyline, index)
    latitude += latitude_part
    longitude += longitude_part
    time_stamp += time_part
    gpx_log = _get_gpx_from_decoded(latitude, longitude, time_stamp)
    gpx_logs.push(gpx_log)
  end
  gpx_logs
end

.encode_time_aware_polyline(gpx_logs) ⇒ Object 



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# File 'lib/time_aware_polyline.rb', line 5

def self.encode_time_aware_polyline(gpx_logs)
  _extend_time_aware_polyline(:gpx_logs => gpx_logs)
end