com.vividsolutions.jts.algorithm.match.HausdorffSimilarityMeasure Maven / Gradle / Ivy
/*
* The JTS Topology Suite is a collection of Java classes that
* implement the fundamental operations required to validate a given
* geo-spatial data set to a known topological specification.
*
* Copyright (C) 2001 Vivid Solutions
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* For more information, contact:
*
* Vivid Solutions
* Suite #1A
* 2328 Government Street
* Victoria BC V8T 5G5
* Canada
*
* (250)385-6040
* www.vividsolutions.com
*/
package com.vividsolutions.jts.algorithm.match;
import com.vividsolutions.jts.geom.*;
import com.vividsolutions.jts.algorithm.distance.*;
/**
* Measures the degree of similarity between two {@link Geometry}s
* using the Hausdorff distance metric.
* The measure is normalized to lie in the range [0, 1].
* Higher measures indicate a great degree of similarity.
*
* The measure is computed by computing the Hausdorff distance
* between the input geometries, and then normalizing
* this by dividing it by the diagonal distance across
* the envelope of the combined geometries.
*
* @author mbdavis
*
*/
public class HausdorffSimilarityMeasure
implements SimilarityMeasure
{
/*
public static double measure(Geometry a, Geometry b)
{
HausdorffSimilarityMeasure gv = new HausdorffSimilarityMeasure(a, b);
return gv.measure();
}
*/
public HausdorffSimilarityMeasure()
{
}
/*
* Densify a small amount to increase accuracy of Hausdorff distance
*/
private static final double DENSIFY_FRACTION = 0.25;
public double measure(Geometry g1, Geometry g2)
{
double distance = DiscreteHausdorffDistance.distance(g1, g2, DENSIFY_FRACTION);
Envelope env = new Envelope(g1.getEnvelopeInternal());
env.expandToInclude(g2.getEnvelopeInternal());
double envSize = diagonalSize(env);
// normalize so that more similarity produces a measure closer to 1
double measure = 1 - distance / envSize;
//System.out.println("Hausdorff distance = " + distance + ", measure = " + measure);
return measure;
}
public static double diagonalSize(Envelope env)
{
if (env.isNull()) return 0.0;
double width = env.getWidth();
double hgt = env.getHeight();
return Math.sqrt(width * width + hgt * hgt);
}
}