net.studioblueplanet.generics

Class DPUtil

java.lang.Object

net.studioblueplanet.generics.DPUtil

public class DPUtil
extends Object

Implementation of the Douglas-Peucker algorithm.

Author:

https://programmersought.com/article/54684929685/

Constructor Summary

Constructors

Constructor and Description
DPUtil()

Method Summary

Modifier and Type	Method and Description
static void	compression(List<ActivityRecord> originPoints, List<ActivityRecord> resultPoints, int start, int end, double dMax) Function: According to the maximum distance limit, the original trajectory is recursively sampled by the DP method to obtain the compressed trajectory
static double	distToSegment(ActivityRecord pA, ActivityRecord pB, ActivityRecord pX) Function: use the triangle area (calculated by Helen's formula) equal method to calculate the distance from point pX to the straight line determined by points pA and pB
static List<ActivityRecord>	dpAlgorithm(List<ActivityRecord> originPoints, Double dMax) DP algorithm entry Pass in the set of track points before compression Output the compressed result track point collection
static double	geoDist(ActivityRecord pA, ActivityRecord pB) Function: Find the distance between two latitude and longitude points according to mathematical formulas

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

DPUtil

public DPUtil()

Method Detail

dpAlgorithm

public static List<ActivityRecord> dpAlgorithm(List<ActivityRecord> originPoints,
                                               Double dMax)

DP algorithm entry Pass in the set of track points before compression Output the compressed result track point collection

Parameters:

originPoints - The collection of track points before compression

dMax - Maximum distance error threshold from point to track

Returns:

The compressed and sorted list of GPS coordinates

compression

public static void compression(List<ActivityRecord> originPoints,
                               List<ActivityRecord> resultPoints,
                               int start,
                               int end,
                               double dMax)

Function: According to the maximum distance limit, the original trajectory is recursively sampled by the DP method to obtain the compressed trajectory

Parameters:

originPoints: - the original latitude and longitude coordinate point array

resultPoints: - keep the filtered point coordinate array

start: - starting subscript

end: - end subscript

dMax: - pre-specified maximum distance error calculation

distToSegment

public static double distToSegment(ActivityRecord pA,
                                   ActivityRecord pB,
                                   ActivityRecord pX)

Function: use the triangle area (calculated by Helen's formula) equal method to calculate the distance from point pX to the straight line determined by points pA and pB

Parameters:

pA: - starting point

pB: - end point

pX: - The third point

Returns:

distance: the distance from point pX to the line where pA and pB are located

geoDist

public static double geoDist(ActivityRecord pA,
                             ActivityRecord pB)

Function: Find the distance between two latitude and longitude points according to mathematical formulas

Parameters:

pA: - starting point

pB: - end point

Returns:

distance: distance in m