Application: gvSIG desktop » gvSIG geoprocess

/*

 * Created on 23-abr-2007

 *

 * gvSIG. Sistema de Informaci?n Geogr?fica de la Generalitat Valenciana

 *

 * Copyright (C) 2004 IVER T.I. and Generalitat Valenciana.

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public License

 * as published by the Free Software Foundation; either version 2

 * of the License, or (at your option) any later version.

 *

 * This program 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 General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307,USA.

 *

 * For more information, contact:

 *

 *  Generalitat Valenciana

 *   Conselleria d'Infraestructures i Transport

 *   Av. Blasco Ib??ez, 50

 *   46010 VALENCIA

 *   SPAIN

 *

 *      +34 963862235

 *   gvsig@gva.es

 *      www.gvsig.gva.es

 *

 *    or

 *

 *   IVER T.I. S.A

 *   Salamanca 50

 *   46005 Valencia

 *   Spain

 *

 *   +34 963163400

 *   dac@iver.es

 */

/* CVS MESSAGES:

*

* $Id: JTSFacade.java 12946 2007-08-07 15:08:11Z azabala $

* $Log$

* Revision 1.1  2007-08-07 15:08:11  azabala

* new version in cvs. centralizes all jts stuff

*

*

*/

package org.gvsig.geoprocess.algorithm.base.util;

import org.gvsig.fmap.geom.Geometry.TYPES;

import com.vividsolutions.jts.geom.Geometry;

import com.vividsolutions.jts.geom.GeometryCollection;

import com.vividsolutions.jts.geom.GeometryFactory;

import com.vividsolutions.jts.precision.EnhancedPrecisionOp;

/**

 * 

 * Instead of calling individual methods of JTS (JTS Topology Suite),

 * this singleton facade allows gvSIG users to centralize all JTS computational

 * geometry operations in one only class.

 * 

 * This is useful to ensure certain operations

 * (for example, geoprocessing operations could cause robustness problems, so JTS

 * allows to use enhanced precission operations, this facade forces to use these

 * enhanced precision operations)

 * 

 * @author alvaro zabala

 * 

 */

public class JTSFacade {

        public static Geometry computeBuffer(Geometry originalGeometry, double distance){

                return EnhancedPrecisionOp.buffer(originalGeometry, distance);        

        }

        public static Geometry difference(Geometry geom1, Geometry geom2){

                return EnhancedPrecisionOp.difference(geom1, geom2);

        }

        public static Geometry symDifference(Geometry geom1, Geometry geom2){

                return EnhancedPrecisionOp.symDifference(geom1, geom2);

        }

        public static Geometry union(Geometry geom1, Geometry geom2){

                return EnhancedPrecisionOp.union(geom1, geom2);

        }

        public static Geometry union(Geometry[] geomArray, int geometryType){

                if(geomArray.length == 0)

                        return null;

                if(geomArray.length == 1)

                        return geomArray[0];

                if(geometryType == TYPES.SURFACE || 

                        geometryType == TYPES.CIRCLE || 

                        geometryType == TYPES.ELLIPSE) {

                                GeometryFactory fact = geomArray[0].getFactory();

                                Geometry geomCol = fact.createGeometryCollection(geomArray);

                                return computeBuffer(geomCol, 0d);

                } else {

                        Geometry unionResult = geomArray[0];

                        for(int i = 1; i < geomArray.length; i++)

                                unionResult = union(unionResult, geomArray[i]);

                        return unionResult;

                }

        }

        public static Geometry intersection(Geometry geom1, Geometry geom2){

                return EnhancedPrecisionOp.intersection(geom1, geom2);

        }

        /**

         * Checks a JTS geometry to be null or NIL.

         * NIL in jts is used to represent particular cases of geometries.

         * (for example, an interior buffer that collapses a geometry).

         * NIL is managed with a zero lenght GeometryCollection

         * @param geometry

         * @return

         */

        public static boolean checkNull(Geometry geometry){

                if(geometry == null)

                        return true;

                if(geometry instanceof GeometryCollection){

                        GeometryCollection col = (GeometryCollection)geometry;

                        if(col.getNumGeometries() < 1)

                                return true;

                }

                return false;

        }

}