/*
* This is part of Geomajas, a GIS framework, http://www.geomajas.org/.
*
* Copyright 2008-2011 Geosparc nv, http://www.geosparc.com/, Belgium.
*
* The program is available in open source according to the GNU Affero
* General Public License. All contributions in this program are covered
* by the Geomajas Contributors License Agreement. For full licensing
* details, see LICENSE.txt in the project root.
*/
package org.geomajas.plugin.geocoder.service;
import com.vividsolutions.jts.geom.Coordinate;
import com.vividsolutions.jts.geom.Envelope;
import org.geomajas.geometry.CrsTransform;
import org.geomajas.global.ExceptionCode;
import org.geomajas.global.GeomajasException;
import org.geomajas.service.GeoService;
import org.geotools.geometry.jts.JTS;
import org.opengis.referencing.crs.CoordinateReferenceSystem;
import org.opengis.referencing.operation.TransformException;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
/**
* Utility functions which are needed for the geocoder plugin. These may be candidates to move to the backend module.
*
* @author Joachim Van der Auwera
*/
@Component
public class GeocoderUtilService {
private static final double EXTEND_MAPUNIT_TEST_LENGTH = .1; // start with 1/10 crs unit
private static final double DISTANCE_PRECISION = .001; // mm precision
private static final int EXTEND_MAX_ITERATIONS = 5; // max 5 iterations
@Autowired
private GeoService geoService;
/**
* Transform a {@link Envelope} from the source to the target CRS.
*
* @param source source geometry
* @param sourceCrs source CRS
* @param targetCrs target CRS
* @return transformed source, now in target CRS
* @throws GeomajasException building the transformation or doing the transformation is not possible
*/
public Envelope transform(Envelope source, CoordinateReferenceSystem sourceCrs, CoordinateReferenceSystem targetCrs)
throws GeomajasException {
if (sourceCrs == targetCrs) { // NOPMD
// only works when the caching of the CRSs works
return source;
}
CrsTransform crsTransform = geoService.getCrsTransform(sourceCrs, targetCrs);
return geoService.transform(source, crsTransform);
}
/**
* Build an area around a point with given width and height in meters.
* <p/>
* The calculation tries to get the size right up to mm precision, but it may be less precise as the number of
* attempts to reach the precision are limited.
*
* @param coordinate center for result envelope.
* @param crs crs for coordinate
* @param width width in meters
* @param height height in meters
* @return envelope width requested size (up to mm precision) centered on point
* @throws GeomajasException transformation problems
*/
public Envelope extendPoint(Coordinate coordinate, CoordinateReferenceSystem crs,
double width, double height) throws GeomajasException {
double halfCrsWidth = EXTEND_MAPUNIT_TEST_LENGTH;
double halfCrsHeight = EXTEND_MAPUNIT_TEST_LENGTH;
double x = coordinate.x;
double y = coordinate.y;
for (int i = EXTEND_MAX_ITERATIONS; i > 0; i--) {
try {
Coordinate test;
test = new Coordinate(x + halfCrsWidth, y);
double deltaX = JTS.orthodromicDistance(coordinate, test, crs);
test = new Coordinate(x, y + halfCrsHeight);
double deltaY = JTS.orthodromicDistance(coordinate, test, crs);
if (Math.abs(deltaX - width / 2) < DISTANCE_PRECISION &&
Math.abs(deltaY - height / 2) < DISTANCE_PRECISION) {
break;
}
halfCrsWidth = halfCrsWidth / deltaX * width / 2;
halfCrsHeight = halfCrsHeight / deltaY * height / 2;
} catch (TransformException te) {
throw new GeomajasException(te, ExceptionCode.GEOMETRY_TRANSFORMATION_FAILED, crs);
}
}
return new Envelope(x - halfCrsWidth, x + halfCrsWidth, y - halfCrsHeight, y + halfCrsHeight);
}
}