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/*

 * Created on 07-sep-2007

 *

 * gvSIG. Sistema de Informaci?n Geogr?fica de la Generalitat Valenciana

 *

 * Copyright (C) 2004 IVER T.I. and Generalitat Valenciana.

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public License

 * as published by the Free Software Foundation; either version 2

 * of the License, or (at your option) any later version.

 *

 * This program 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 General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307,USA.

 *

 * For more information, contact:

 *

 *  Generalitat Valenciana

 *   Conselleria d'Infraestructures i Transport

 *   Av. Blasco Ib??ez, 50

 *   46010 VALENCIA

 *   SPAIN

 *

 *      +34 963862235

 *   gvsig@gva.es

 *      www.gvsig.gva.es

 *

 *    or

 *

 *   IVER T.I. S.A

 *   Salamanca 50

 *   46005 Valencia

 *   Spain

 *

 *   +34 963163400

 *   dac@iver.es

 */

/* CVS MESSAGES:

 *

 * $Id: RobustLengthIndexedLine.java 13591 2007-09-09 11:44:09Z azabala $

 * $Log$

 * Revision 1.1  2007-09-09 11:44:09  azabala

 * Improvements to JTS (robustness problems)

 *

 *

 */

package org.gvsig.jts;

import com.vividsolutions.jts.geom.Coordinate;

import com.vividsolutions.jts.geom.Geometry;

import com.vividsolutions.jts.geom.LineSegment;

import com.vividsolutions.jts.geom.PrecisionModel;

import com.vividsolutions.jts.linearref.LengthIndexedLine;

import com.vividsolutions.jts.linearref.LinearIterator;

/**

 * Implementation of LengthIndexedLine to avoid robustness problems.

 * 

 * TODO If JTS official implementation of LenghtIndexedLine solve the problem

 * that has been already reported about precission robustness, DELETE THIS CLASS

 * 

 * @author azabala

 * 

 */

public class RobustLengthIndexedLine extends LengthIndexedLine {

        /**

         * Superclass has no methods to expose linearGeom, and is private, so we

         * need to mantain a reference here

         */

        private Geometry linearGeom;

        public RobustLengthIndexedLine(Geometry arg0) {

                super(arg0);

                this.linearGeom = arg0;

        }

        public double indexOf(Coordinate pt) {

                return indexOfFromStart(pt, -1);

        }

        public double indexOfAfter(Coordinate pt, double minIndex) {

                if (minIndex < 0.0)

                        return indexOf(pt);

                double endIndex = linearGeom.getLength();

                if (endIndex < minIndex)

                        return endIndex;

                double closestAfter = indexOfFromStart(pt, minIndex);

                return closestAfter;

        }

        /**

         * Return the first index ocurrence of the given coordinate grater than

         * minIndex.

         */

        private double indexOfFromStart(Coordinate inputPt, double minIndex) {

                double minDistance = Double.MAX_VALUE;

                double ptMeasure = minIndex;

                double segmentStartMeasure = 0.0;

                LineSegment seg = new LineSegment();

                LinearIterator it = new LinearIterator(linearGeom);

                while (it.hasNext()) {

                        if (!it.isEndOfLine()) {

                                seg.p0 = it.getSegmentStart();

                                seg.p1 = it.getSegmentEnd();

                                double segDistance = seg.distance(inputPt);

/*

 * these two lines of code are the only novelties respect to LenghtIndexedLine

 */

                                PrecisionModel pm = linearGeom.getPrecisionModel();

                                segDistance = pm.makePrecise(segDistance);

/*

 * FIXME Remove them if JTS solve the problem

 */

                                double segMeasureToPt = segmentNearestMeasure(seg, inputPt,

                                                segmentStartMeasure);

                                if (segDistance < minDistance && segMeasureToPt > minIndex) {

                                        ptMeasure = segMeasureToPt;

                                        minDistance = segDistance;

                                }

                                segmentStartMeasure += seg.getLength();

                        }

                        it.next();

                }

                return ptMeasure;

        }

        private double segmentNearestMeasure(LineSegment seg, Coordinate inputPt,

                        double segmentStartMeasure) {

                // found new minimum, so compute location distance of point

                double projFactor = seg.projectionFactor(inputPt);

                if (projFactor <= 0.0)

                        return segmentStartMeasure;

                if (projFactor <= 1.0)

                        return segmentStartMeasure + projFactor * seg.getLength();

                // projFactor > 1.0

                return segmentStartMeasure + seg.getLength();

        }

}