01: /*
02: * The JTS Topology Suite is a collection of Java classes that
03: * implement the fundamental operations required to validate a given
04: * geo-spatial data set to a known topological specification.
05: *
06: * Copyright (C) 2001 Vivid Solutions
07: *
08: * This library is free software; you can redistribute it and/or
09: * modify it under the terms of the GNU Lesser General Public
10: * License as published by the Free Software Foundation; either
11: * version 2.1 of the License, or (at your option) any later version.
12: *
13: * This library is distributed in the hope that it will be useful,
14: * but WITHOUT ANY WARRANTY; without even the implied warranty of
15: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16: * Lesser General Public License for more details.
17: *
18: * You should have received a copy of the GNU Lesser General Public
19: * License along with this library; if not, write to the Free Software
20: * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
21: *
22: * For more information, contact:
23: *
24: * Vivid Solutions
25: * Suite #1A
26: * 2328 Government Street
27: * Victoria BC V8T 5G5
28: * Canada
29: *
30: * (250)385-6040
31: * www.vividsolutions.com
32: */
33: package com.vividsolutions.jts.algorithm;
34:
35: import com.vividsolutions.jts.geom.*;
36:
37: /**
38: * Computes the centroid of a point geometry.
39: * <h2>Algorithm</h2>
40: * Compute the average of all points.
41: *
42: * @version 1.7
43: */
44: public class CentroidPoint {
45: private int ptCount = 0;
46: private Coordinate centSum = new Coordinate();
47:
48: public CentroidPoint() {
49: }
50:
51: /**
52: * Adds the point(s) defined by a Geometry to the centroid total.
53: * If the geometry is not of dimension 0 it does not contribute to the centroid.
54: * @param geom the geometry to add
55: */
56: public void add(Geometry geom) {
57: if (geom instanceof Point) {
58: add(geom.getCoordinate());
59: } else if (geom instanceof GeometryCollection) {
60: GeometryCollection gc = (GeometryCollection) geom;
61: for (int i = 0; i < gc.getNumGeometries(); i++) {
62: add(gc.getGeometryN(i));
63: }
64: }
65: }
66:
67: /**
68: * Adds the length defined by an array of coordinates.
69: * @param pts an array of {@link Coordinate}s
70: */
71: public void add(Coordinate pt) {
72: ptCount += 1;
73: centSum.x += pt.x;
74: centSum.y += pt.y;
75: }
76:
77: public Coordinate getCentroid() {
78: Coordinate cent = new Coordinate();
79: cent.x = centSum.x / ptCount;
80: cent.y = centSum.y / ptCount;
81: return cent;
82: }
83:
84: }
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