com.vividsolutions.jts.algorithm.CentroidLine Maven / Gradle / Ivy
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/*
* 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 the centroid of a linear geometry.
* Algorithm
* Compute the average of the midpoints
* of all line segments weighted by the segment length.
*
* @version 1.7
* @deprecated use Centroid instead
*/
public class CentroidLine
{
private Coordinate centSum = new Coordinate();
private double totalLength = 0.0;
public CentroidLine()
{
}
/**
* Adds the linear components of by a Geometry to the centroid total.
* If the geometry has no linear components it does not contribute to the centroid,
*
* @param geom the geometry to add
*/
public void add(Geometry geom)
{
if (geom instanceof LineString) {
add(geom.getCoordinates());
}
else if (geom instanceof Polygon) {
Polygon poly = (Polygon) geom;
// add linear components of a polygon
add(poly.getExteriorRing().getCoordinates());
for (int i = 0; i < poly.getNumInteriorRing(); i++) {
add(poly.getInteriorRingN(i).getCoordinates());
}
}
else if (geom instanceof GeometryCollection) {
GeometryCollection gc = (GeometryCollection) geom;
for (int i = 0; i < gc.getNumGeometries(); i++) {
add(gc.getGeometryN(i));
}
}
}
public Coordinate getCentroid()
{
Coordinate cent = new Coordinate();
cent.x = centSum.x / totalLength;
cent.y = centSum.y / totalLength;
return cent;
}
/**
* Adds the length defined by an array of coordinates.
* @param pts an array of {@link Coordinate}s
*/
public void add(Coordinate[] pts)
{
for (int i = 0; i < pts.length - 1; i++) {
double segmentLen = pts[i].distance(pts[i + 1]);
totalLength += segmentLen;
double midx = (pts[i].x + pts[i + 1].x) / 2;
centSum.x += segmentLen * midx;
double midy = (pts[i].y + pts[i + 1].y) / 2;
centSum.y += segmentLen * midy;
}
}
}