com.graphhopper.util

Class DouglasPeucker

java.lang.Object

com.graphhopper.util.DouglasPeucker

public class DouglasPeucker
extends Object

Simplifies a list of 2D points which are not too far away. http://en.wikipedia.org/wiki/Ramer%E2%80%93Douglas%E2%80%93Peucker_algorithm

Calling simplify is thread safe.

Author:

Peter Karich

Constructor Summary

Constructors

Constructor and Description
DouglasPeucker()

Method Summary

Modifier and Type	Method and Description
void	setApproximation(boolean a)
DouglasPeucker	setMaxDistance(double dist) maximum distance of discrepancy (from the normal way) in meter
int	simplify(PointList points) Simplifies the points, from index 0 to size-1.
int	simplify(PointList points, int fromIndex, int lastIndex)
int	simplify(PointList points, int fromIndex, int lastIndex, boolean compress) Simplifies a part of the points.

Methods inherited from class java.lang.Object

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

Constructor Detail

DouglasPeucker

public DouglasPeucker()

Method Detail

setApproximation

public void setApproximation(boolean a)

setMaxDistance

public DouglasPeucker setMaxDistance(double dist)

maximum distance of discrepancy (from the normal way) in meter

simplify

public int simplify(PointList points)

Simplifies the points, from index 0 to size-1.

It is a wrapper method for simplify(PointList, int, int).

Returns:

The number removed points

simplify

public int simplify(PointList points,
                    int fromIndex,
                    int lastIndex)

simplify

public int simplify(PointList points,
                    int fromIndex,
                    int lastIndex,
                    boolean compress)

Simplifies a part of the points. The fromIndex and lastIndex are guaranteed to be kept.

Parameters:

points - The PointList to simplify

fromIndex - Start index to simplify, should be <= lastIndex

lastIndex - Simplify up to this index

compress - Whether or not the points shall be compressed or not, if set to false no points are actually removed, but instead their lat/lon/ele is only set to NaN

Returns:

The number of removed points