org.locationtech.jts.algorithm.distance

Class DiscreteFrechetDistance

java.lang.Object

org.locationtech.jts.algorithm.distance.DiscreteFrechetDistance

public class DiscreteFrechetDistance
extends Object

The Fréchet distance is a measure of similarity between curves. Thus, it can be used like the Hausdorff distance.

An analogy for the Fréchet distance taken from Computing Discrete Fréchet Distance

 A man is walking a dog on a leash: the man can move
 on one curve, the dog on the other; both may vary their
 speed, but backtracking is not allowed.
 

Its metric is better than the Hausdorff distance because it takes the directions of the curves into account. It is possible that two curves have a small Hausdorff but a large Fréchet distance.

This implementation is base on the following optimized Fréchet distance algorithm:

Thomas Devogele, Maxence Esnault, Laurent Etienne. Distance discrète de Fréchet optimisée. Spatial
 Analysis and Geomatics (SAGEO), Nov 2016, Nice, France. hal-02110055

Several matrix storage implementations are provided

See Also:

Fréchet distance, Computing Discrete Fréchet Distance, Distance discrète de Fréchet optimisée, Fast Discrete Fréchet Distance

Constructor Summary

Constructors

Constructor and Description
DiscreteFrechetDistance(Geometry g0, Geometry g1) Creates an instance of this class using the provided geometries.

Method Summary

Modifier and Type	Method and Description
static double	distance(Geometry g0, Geometry g1) Computes the Discrete Fréchet Distance between two Geometrys using a Cartesian distance computation function.
Coordinate[]	getCoordinates() Gets the pair of Coordinates at which the distance is obtained.

Methods inherited from class java.lang.Object

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

Constructor Detail

DiscreteFrechetDistance

public DiscreteFrechetDistance(Geometry g0,
                               Geometry g1)

Creates an instance of this class using the provided geometries.

Parameters:

g0 - a geometry

g1 - a geometry

Method Detail

distance

public static double distance(Geometry g0,
                              Geometry g1)

Computes the Discrete Fréchet Distance between two Geometrys using a Cartesian distance computation function.

Parameters:

g0 - the 1st geometry

g1 - the 2nd geometry

Returns:

the cartesian distance between {#g0} and {#g1}

getCoordinates

public Coordinate[] getCoordinates()

Gets the pair of Coordinates at which the distance is obtained.

Returns:

the pair of Coordinates at which the distance is obtained