/* * 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.noding; import java.util.*; import com.vividsolutions.jts.index.SpatialIndex; import com.vividsolutions.jts.index.chain.*; import com.vividsolutions.jts.index.strtree.STRtree; import com.vividsolutions.jts.noding.SegmentIntersector; import com.vividsolutions.jts.noding.SegmentString; /** * Intersects two sets of {@link SegmentString}s using a index based * on {@link MonotoneChain}s and a {@link SpatialIndex}. * * @version 1.7 */ public class MCIndexSegmentSetMutualIntersector extends SegmentSetMutualIntersector { /* * The {@link SpatialIndex} used should be something that supports * envelope (range) queries efficiently (such as a {@link Quadtree} * or {@link STRtree}. */ private SpatialIndex index= new STRtree(); private int indexCounter = 0; private int processCounter = 0; // statistics private int nOverlaps = 0; public MCIndexSegmentSetMutualIntersector() { } public SpatialIndex getIndex() { return index; } public void setBaseSegments(Collection segStrings) { for (Iterator i = segStrings.iterator(); i.hasNext(); ) { addToIndex((SegmentString) i.next()); } } private void addToIndex(SegmentString segStr) { List segChains = MonotoneChainBuilder.getChains(segStr.getCoordinates(), segStr); for (Iterator i = segChains.iterator(); i.hasNext(); ) { MonotoneChain mc = (MonotoneChain) i.next(); mc.setId(indexCounter++); index.insert(mc.getEnvelope(), mc); } } public void process(Collection segStrings) { processCounter = indexCounter + 1; nOverlaps = 0; List monoChains = new ArrayList(); for (Iterator i = segStrings.iterator(); i.hasNext(); ) { addToMonoChains((SegmentString) i.next(), monoChains); } intersectChains(monoChains); // System.out.println("MCIndexBichromaticIntersector: # chain overlaps = " + nOverlaps); // System.out.println("MCIndexBichromaticIntersector: # oct chain overlaps = " + nOctOverlaps); } private void intersectChains(List monoChains) { MonotoneChainOverlapAction overlapAction = new SegmentOverlapAction(segInt); for (Iterator i = monoChains.iterator(); i.hasNext(); ) { MonotoneChain queryChain = (MonotoneChain) i.next(); List overlapChains = index.query(queryChain.getEnvelope()); for (Iterator j = overlapChains.iterator(); j.hasNext(); ) { MonotoneChain testChain = (MonotoneChain) j.next(); queryChain.computeOverlaps(testChain, overlapAction); nOverlaps++; if (segInt.isDone()) return; } } } private void addToMonoChains(SegmentString segStr, List monoChains) { List segChains = MonotoneChainBuilder.getChains(segStr.getCoordinates(), segStr); for (Iterator i = segChains.iterator(); i.hasNext(); ) { MonotoneChain mc = (MonotoneChain) i.next(); mc.setId(processCounter++); monoChains.add(mc); } } public class SegmentOverlapAction extends MonotoneChainOverlapAction { private SegmentIntersector si = null; public SegmentOverlapAction(SegmentIntersector si) { this.si = si; } public void overlap(MonotoneChain mc1, int start1, MonotoneChain mc2, int start2) { SegmentString ss1 = (SegmentString) mc1.getContext(); SegmentString ss2 = (SegmentString) mc2.getContext(); si.processIntersections(ss1, start1, ss2, start2); } } }