/* * 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.locate; import java.util.*; import com.vividsolutions.jts.algorithm.RayCrossingCounter; import com.vividsolutions.jts.geom.*; import com.vividsolutions.jts.geom.util.*; import com.vividsolutions.jts.index.*; import com.vividsolutions.jts.index.intervalrtree.*; /** * Determines the {@link Location} of {@link Coordinate}s relative to * a {@link Polygonal} geometry, using indexing for efficiency. * This algorithm is suitable for use in cases where * many points will be tested against a given area. * * @author Martin Davis * */ public class IndexedPointInAreaLocator implements PointOnGeometryLocator { private IntervalIndexedGeometry index; /** * Creates a new locator for a given {@link Geometry} * @param g the Geometry to locate in */ public IndexedPointInAreaLocator(Geometry g) { if (! (g instanceof Polygonal)) throw new IllegalArgumentException("Argument must be Polygonal"); buildIndex(g); } private void buildIndex(Geometry g) { index = new IntervalIndexedGeometry(g); } /** * Determines the {@link Location} of a point in an areal {@link Geometry}. * * @param p the point to test * @return the location of the point in the geometry */ public int locate(Coordinate p) { RayCrossingCounter rcc = new RayCrossingCounter(p); SegmentVisitor visitor = new SegmentVisitor(rcc); index.query(p.y, p.y, visitor); /* // MD - slightly slower alternative List segs = index.query(p.y, p.y); countSegs(rcc, segs); */ return rcc.getLocation(); } private static class SegmentVisitor implements ItemVisitor { private RayCrossingCounter counter; public SegmentVisitor(RayCrossingCounter counter) { this.counter = counter; } public void visitItem(Object item) { LineSegment seg = (LineSegment) item; counter.countSegment(seg.getCoordinate(0), seg.getCoordinate(1)); } } private static class IntervalIndexedGeometry { private SortedPackedIntervalRTree index= new SortedPackedIntervalRTree(); public IntervalIndexedGeometry(Geometry geom) { init(geom); } private void init(Geometry geom) { List lines = LinearComponentExtracter.getLines(geom); for (Iterator i = lines.iterator(); i.hasNext(); ) { LineString line = (LineString) i.next(); Coordinate[] pts = line.getCoordinates(); addLine(pts); } } private void addLine(Coordinate[] pts) { for (int i = 1; i < pts.length; i++) { LineSegment seg = new LineSegment(pts[i-1], pts[i]); double min = Math.min(seg.p0.y, seg.p1.y); double max = Math.max(seg.p0.y, seg.p1.y); index.insert(min, max, seg); } } public List query(double min, double max) { ArrayListVisitor visitor = new ArrayListVisitor(); index.query(min, max, visitor); return visitor.getItems(); } public void query(double min, double max, ItemVisitor visitor) { index.query(min, max, visitor); } } }