/* * 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; import com.vividsolutions.jts.geom.*; /** * Computes a point in the interior of an linear geometry. * <h2>Algorithm</h2> * <ul> * <li>Find an interior vertex which is closest to * the centroid of the linestring. * <li>If there is no interior vertex, find the endpoint which is * closest to the centroid. * </ul> * * @version 1.7 */ public class InteriorPointLine { private Coordinate centroid; private double minDistance = Double.MAX_VALUE; private Coordinate interiorPoint = null; public InteriorPointLine(Geometry g) { centroid = g.getCentroid().getCoordinate(); addInterior(g); if (interiorPoint == null) addEndpoints(g); } public Coordinate getInteriorPoint() { return interiorPoint; } /** * Tests the interior vertices (if any) * defined by a linear Geometry for the best inside point. * If a Geometry is not of dimension 1 it is not tested. * @param geom the geometry to add */ private void addInterior(Geometry geom) { if (geom instanceof LineString) { addInterior(geom.getCoordinates()); } else if (geom instanceof GeometryCollection) { GeometryCollection gc = (GeometryCollection) geom; for (int i = 0; i < gc.getNumGeometries(); i++) { addInterior(gc.getGeometryN(i)); } } } private void addInterior(Coordinate[] pts) { for (int i = 1; i < pts.length - 1; i++) { add(pts[i]); } } /** * Tests the endpoint vertices * defined by a linear Geometry for the best inside point. * If a Geometry is not of dimension 1 it is not tested. * @param geom the geometry to add */ private void addEndpoints(Geometry geom) { if (geom instanceof LineString) { addEndpoints(geom.getCoordinates()); } else if (geom instanceof GeometryCollection) { GeometryCollection gc = (GeometryCollection) geom; for (int i = 0; i < gc.getNumGeometries(); i++) { addEndpoints(gc.getGeometryN(i)); } } } private void addEndpoints(Coordinate[] pts) { add(pts[0]); add(pts[pts.length - 1]); } private void add(Coordinate point) { double dist = point.distance(centroid); if (dist < minDistance) { interiorPoint = new Coordinate(point); minDistance = dist; } } }