/*
* 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;
}
}
}