ST_MakeEnvelope.java

/**
 * H2GIS is a library that brings spatial support to the H2 Database Engine
 * <http://www.h2database.com>. H2GIS is developed by CNRS
 * <http://www.cnrs.fr/>.
 *
 * This code is part of the H2GIS project. H2GIS 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;
 * version 3.0 of the License.
 *
 * H2GIS 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 <http://www.gnu.org/licenses/>.
 *
 *
 * For more information, please consult: <http://www.h2gis.org/>
 * or contact directly: info_at_h2gis.org
 */

package org.h2gis.functions.spatial.create;

import com.vividsolutions.jts.geom.Coordinate;
import com.vividsolutions.jts.geom.GeometryFactory;
import com.vividsolutions.jts.geom.Polygon;
import org.h2gis.api.DeterministicScalarFunction;

/**
 * Creates a rectangular POLYGON formed from the given x and y minima.  The user may specify an SRID; if no SRID is specified the unknown spatial reference system is assumed.
 *
 * @author Erwan Bocher
 */
public class ST_MakeEnvelope extends DeterministicScalarFunction {

    private static final GeometryFactory GF = new GeometryFactory();

    public ST_MakeEnvelope() {
        addProperty(PROP_REMARKS,
                "Creates a rectangular POLYGON formed from the given x and y minima.\n"
                + " The user may specify an SRID; if no SRID is specified the unknown\n"
                + " spatial reference system is assumed.");
    }

    @Override
    public String getJavaStaticMethod() {
        return "makeEnvelope";
    }

    /**
     * Creates a rectangular Polygon formed from the minima and maxima by the
     * given shell.
     *
     * @param xmin X min
     * @param ymin Y min
     * @param xmax X max
     * @param ymax Y max
     * @return Envelope as a POLYGON
     */
    public static Polygon makeEnvelope(double xmin, double ymin, double xmax, double ymax) {
        Coordinate[] coordinates = new Coordinate[]{
            new Coordinate(xmin, ymin),
            new Coordinate(xmax, ymin),
            new Coordinate(xmax, ymax),
            new Coordinate(xmin, ymax),
            new Coordinate(xmin, ymin)
        };
        return GF.createPolygon(GF.createLinearRing(coordinates), null);
    }

    /**
     * Creates a rectangular Polygon formed from the minima and maxima by the
     * given shell.
     * The user can set a srid.
     * @param xmin X min
     * @param ymin Y min
     * @param xmax X max
     * @param ymax Y max
     * @param srid SRID
     * @return Envelope as a POLYGON
     */
    public static Polygon makeEnvelope(double xmin, double ymin, double xmax, double ymax, int srid) {
        Polygon geom = makeEnvelope(xmin, ymin, xmax, ymax);
        geom.setSRID(srid);
        return geom;
    }
}