/*
* GeoTools - The Open Source Java GIS Toolkit
* http://geotools.org
*
* (C) 2002-2008, Open Source Geospatial Foundation (OSGeo)
*
* 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;
* version 2.1 of the License.
*
* 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.
*/
package org.geotools.renderer.crs;
import org.geotools.geometry.jts.JTS;
import org.geotools.geometry.jts.ReferencedEnvelope;
import org.geotools.referencing.CRS;
import org.geotools.referencing.operation.projection.EquidistantConic;
import org.geotools.referencing.operation.projection.LambertConformal;
import org.geotools.referencing.operation.projection.LambertConformal1SP;
import org.geotools.referencing.operation.projection.MapProjection;
import org.geotools.referencing.operation.projection.MapProjection.AbstractProvider;
import org.opengis.parameter.ParameterValueGroup;
import org.opengis.referencing.FactoryException;
import org.opengis.referencing.crs.CoordinateReferenceSystem;
import com.vividsolutions.jts.geom.Envelope;
import com.vividsolutions.jts.geom.MultiPolygon;
import com.vividsolutions.jts.geom.Polygon;
/**
* Returns a {@link ProjectionHandler} for the {@link LambertConformal} projection
* that will cut geometries too close to pole on the open ended side of the cone.
*
* @author Andrea Aime - GeoSolutions
*
* @source $URL$
*/
public class ConiclHandlerFactory implements ProjectionHandlerFactory {
static final double EPS = 0.1;
static final double MAX_DISTANCE = 44;
public ProjectionHandler getHandler(ReferencedEnvelope renderingEnvelope, CoordinateReferenceSystem sourceCrs, boolean wrap, int maxWraps) throws FactoryException {
if(renderingEnvelope == null) {
return null;
}
MapProjection mapProjection = CRS.getMapProjection(renderingEnvelope
.getCoordinateReferenceSystem());
if(mapProjection instanceof LambertConformal || mapProjection instanceof EquidistantConic) {
ParameterValueGroup params = mapProjection.getParameterValues();
double centralMeridian = params.parameter(
AbstractProvider.CENTRAL_MERIDIAN.getName().getCode()).doubleValue();
double minLat , maxLat;
double latitudeOrigin;
if (mapProjection instanceof LambertConformal1SP) {
latitudeOrigin = params.parameter(
AbstractProvider.LATITUDE_OF_ORIGIN.getName().getCode()).doubleValue();
} else {
double stdParallel1 = params.parameter(
AbstractProvider.STANDARD_PARALLEL_1.getName().getCode()).doubleValue();
double stdParallel2 = params.parameter(
AbstractProvider.STANDARD_PARALLEL_2.getName().getCode()).doubleValue();
latitudeOrigin = (stdParallel1 + stdParallel2) / 2;
}
if(latitudeOrigin > 0) {
minLat = Math.max(-89, latitudeOrigin - MAX_DISTANCE);
maxLat = 90;
} else {
minLat = -90;
maxLat = Math.min(89, latitudeOrigin + MAX_DISTANCE);
}
if(centralMeridian != 0) {
// we need to divide geometries crossing the central antimeridian in two
double antiMeridian = centralMeridian > 0 ? centralMeridian - 180 : centralMeridian + 180;
Polygon beforeAntiMeridian = JTS.toGeometry(new Envelope(-180, antiMeridian - EPS, minLat, maxLat));
Polygon afterAntiMeridian = JTS.toGeometry(new Envelope(antiMeridian + EPS, 180, minLat, maxLat));
MultiPolygon mask = beforeAntiMeridian.getFactory().createMultiPolygon(new Polygon[] {beforeAntiMeridian, afterAntiMeridian});
return new ProjectionHandler(sourceCrs, mask, renderingEnvelope);
} else {
// for this case we just need to cut on the valid area, which is the whole world
// minus a tiny area around the dateline
Envelope validArea = new Envelope(-180 + EPS, 180 - EPS, minLat, maxLat);
return new ProjectionHandler(sourceCrs, validArea, renderingEnvelope);
}
}
return null;
}
}