Kjell-
Kjell Roang wrote:
I fully agree. I would try to use VisAd as much as possible, and the
conversation with you has given me hints how to use another projection
package inside VisAd. I must then find a way to put GRIB data into VisAd and
get images and data out of VisAd.
I've attached a copy of a version of ProjectionCoordinateSystem
from our IDV package that shows how we adapt our Projection
class (ucar.unidata.geoloc.Projection) to a VisADCoordinateSystem.
This is an older version (we've made mods for other reasons that
are not applicable here), but should give you a guide for
how to convert a GeoTools Projection to a VisADCoordinateSystem.
Don
*************************************************************
Don Murray UCAR Unidata Program
dmurray@xxxxxxxxxxxxxxxx P.O. Box 3000
(303) 497-8628 Boulder, CO 80307
http://www.unidata.ucar.edu/staff/donm
*************************************************************
// $Id: ProjectionCoordinateSystem.java,v 1.5 2001/11/06 17:18:44 dmurray Exp $
/*
* Copyright 1997-2000 Unidata Program Center/University Corporation for
* Atmospheric Research, P.O. Box 3000, Boulder, CO 80307,
* support@xxxxxxxxxxxxxxxx.
*
* 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; either version 2.1 of the License, or (at
* your option) any later version.
*
* 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.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library; if not, write to the Free Software Foundation,
* Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package ucar.visad;
import ucar.unidata.geoloc.*;
import visad.*;
import visad.georef.MapProjection;
/**
* Adapts a ucar.unidata.Projection into a VisAD MapProjection CoordinateSystem.
* Transforms between world coordinates (x,y) in km and lat/lon in degrees.
* Reference is lat/lon (RealTupleType.LatitudeLongitudeTuple)
*
* @see ucar.unidata.geoloc.Projection
* @see visad.georef.MapProjection
* @author Stuart Wier
* @author Don Murray
* @version $Revision: 1.5 $ $Date: 2001/11/06 17:18:44 $
*/
public class ProjectionCoordinateSystem extends MapProjection {
private Projection projection;
private ProjectionPointImpl workP = new ProjectionPointImpl();
private LatLonPointImpl workL = new LatLonPointImpl();
/**
* Constructs an instance from the supplied Projection. The
* reference coordinate system is RealTupleType.LatitudeLongitudeTuple;
* the incoming units are assumed to be km (1000 m).
*/
public ProjectionCoordinateSystem (Projection projection)
throws VisADException
{
super(RealTupleType.LatitudeLongitudeTuple,
new Unit[] {CommonUnit.meter.scale(1000.0),
CommonUnit.meter.scale(1000.0)});
this.projection = projection;
}
/**
* Get a reasonable bounding box in this coordinate system. MapProjections
* are typically specific to an area of the world; there's no bounding
* box that works for all projections so each subclass must implement
* this method.
*
* @return the default MapArea of the Projection
*/
public java.awt.geom.Rectangle2D getDefaultMapArea()
{
return projection.getDefaultMapArea();
}
/**
* Get the Projection used for the transformations.
* @return projection
*/
public Projection getProjection() {
return projection;
}
/**
* Convert world coordinates to lat/lon. Input coords are in km.
* @param world world projection coordinates (x = world[0][i])
* @return corresponding lat/lon values (lat = latlon[0][i])
* @throws VisADException world coordinate array length != 2
*/
public double[][] toReference(double[][] world)
throws VisADException
{
if ( world == null || world.length != 2)
throw new VisADException(
"ProjectionCoordinateSystem.toReference: " +
"null world array or wrong dimension ");
double[][] latlon = new double[2][world[0].length];
LatLonPoint llPoint;
for (int i = 0; i < latlon[0].length; i++)
{
workP.setLocation(world[0][i], world[1][i]);
llPoint = projection.projToLatLon(workP);
latlon[getLatitudeIndex()][i] = llPoint.getLatitude();
latlon[getLongitudeIndex()][i] = llPoint.getLongitude();
}
return latlon;
}
/**
* Convert lat/lon coordinates to world (projection) coords.
* @param lat/lon values (lat = latlon[0][i])
* @return world projection coordinates (x = world[0][i])
* @throws VisADException latlon coordinate array length != 2
*/
public double[][] fromReference(double[][] latlon)
throws VisADException
{
if ( latlon == null || latlon.length != 2)
throw new VisADException(
"ProjectionCoordinateSystem.toReference: " +
"null latlon array or wrong dimension ");
double[][] world = new double[2][latlon[0].length];
ProjectionPoint projPoint;
for (int i = 0; i < latlon[0].length; i++)
{
workL.setLatitude(latlon[getLatitudeIndex()][i]);
workL.setLongitude(latlon[getLongitudeIndex()][i]);
projPoint = projection.latLonToProj(workL);
world[0][i] = projPoint.getX();
world[1][i] = projPoint.getY();
}
return world;
}
/**
* Check for equality of CoordinateSystem objects
* @param obj other object in question
* @return true if the object in question is a ProjectionCoordinateSystem
* and it's Projection is equal the this object's Projection
*/
public boolean equals (Object obj)
{
if (!(obj instanceof ProjectionCoordinateSystem))
return false;
ProjectionCoordinateSystem that = (ProjectionCoordinateSystem) obj;
return that.projection.equals(projection);
}
} // end ProjectionCoordinateSystem class
