Vessel Trajectory Data Compression Algorithm considering Critical Region Identification

Algorithm 2

Douglas–Peucker algorithm.

	Input: Ship latitude and longitude coordinates information Point.
	Distance Threshold
	Output: Compressed ship latitude and longitude information Pointset.
(1)	Pointset = list()
(2)	Calculate the list of distances from the point to the first and last line
(3)	Get the maximum value of the list species and the maximum position
(4)	If < T then
(5)	Return to the first and last point
(6)	Else
(7)	L-Point = DP(Point(0: index), T)
(8)	R-Point = DP(Point(index: end), T)
(9)	Pointset. append(L-Point)
(10)	Pointset. append(R-Point)
(11)	end if
	return Pointset