com.vividsolutions.jts.operation.union.PointGeometryUnion Maven / Gradle / Ivy
/*
* 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.operation.union;
import com.vividsolutions.jts.algorithm.*;
import com.vividsolutions.jts.geom.*;
import com.vividsolutions.jts.geom.util.*;
import java.util.*;
/**
* Computes the union of a {@link Puntal} geometry with
* another arbitrary {@link Geometry}.
* Does not copy any component geometries.
*
* @author mbdavis
*
*/
public class PointGeometryUnion
{
public static Geometry union(Puntal pointGeom, Geometry otherGeom)
{
PointGeometryUnion unioner = new PointGeometryUnion(pointGeom, otherGeom);
return unioner.union();
}
private Geometry pointGeom;
private Geometry otherGeom;
private GeometryFactory geomFact;
public PointGeometryUnion(Puntal pointGeom, Geometry otherGeom)
{
this.pointGeom = (Geometry) pointGeom;
this.otherGeom = otherGeom;
geomFact = otherGeom.getFactory();
}
public Geometry union()
{
PointLocator locater = new PointLocator();
// use a set to eliminate duplicates, as required for union
Set exteriorCoords = new TreeSet();
for (int i =0 ; i < pointGeom.getNumGeometries(); i++) {
Point point = (Point) pointGeom.getGeometryN(i);
Coordinate coord = point.getCoordinate();
int loc = locater.locate(coord, otherGeom);
if (loc == Location.EXTERIOR)
exteriorCoords.add(coord);
}
// if no points are in exterior, return the other geom
if (exteriorCoords.size() == 0)
return otherGeom;
// make a puntal geometry of appropriate size
Geometry ptComp = null;
Coordinate[] coords = CoordinateArrays.toCoordinateArray(exteriorCoords);
if (coords.length == 1) {
ptComp = geomFact.createPoint(coords[0]);
}
else {
ptComp = geomFact.createMultiPoint(coords);
}
// add point component to the other geometry
return GeometryCombiner.combine(ptComp, otherGeom);
}
}