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ST_ClosestPoint.java
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ST_ClosestPoint.java
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/**
* H2GIS is a library that brings spatial support to the H2 Database Engine
* <a href="http://www.h2database.com">http://www.h2database.com</a>. H2GIS is developed by CNRS
* <a href="http://www.cnrs.fr/">http://www.cnrs.fr/</a>.
*
* 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: <a href="http://www.h2gis.org/">http://www.h2gis.org/</a>
* or contact directly: info_at_h2gis.org
*/
package org.h2gis.functions.spatial.distance;
import java.sql.SQLException;
import org.h2gis.api.DeterministicScalarFunction;
import org.locationtech.jts.geom.Geometry;
import org.locationtech.jts.geom.Point;
import org.locationtech.jts.operation.distance.DistanceOp;
/**
* ST_ClosestPoint returns the 2D point on geometry A that is closest to
* geometry B. If the closest point is not unique, it returns the first one it
* finds. This means that the point returned depends on the order of the
* geometry's coordinates.
*
* @author Adam Gouge
*/
public class ST_ClosestPoint extends DeterministicScalarFunction {
public ST_ClosestPoint() {
addProperty(PROP_REMARKS, "Returns the 2D point on geometry A that is " +
"closest to geometry B.");
}
@Override
public String getJavaStaticMethod() {
return "closestPoint";
}
/**
* Returns the 2D point on geometry A that is closest to geometry B.
*
* @param geomA Geometry A
* @param geomB Geometry B
* @return The 2D point on geometry A that is closest to geometry B
* @throws java.sql.SQLException
*/
public static Point closestPoint(Geometry geomA, Geometry geomB) throws SQLException {
if (geomA == null || geomB == null) {
return null;
}
if(geomA.getSRID()!=geomB.getSRID()){
throw new SQLException("Operation on mixed SRID geometries not supported");
}
// Return the closest point on geomA. (We would have used index
// 1 to return the closest point on geomB.)
return geomA.getFactory().createPoint(DistanceOp.nearestPoints(geomA, geomB)[0]);
}
}