/*
* GeoTools - The Open Source Java GIS Toolkit
* http://geotools.org
*
* (C) 2001-2008, 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.coverage.processing.operation;
// J2SE dependencies
import java.lang.reflect.Array;
// JAI dependencies
import javax.media.jai.Interpolation;
// OpenGIS dependencies
import org.opengis.coverage.Coverage;
import org.opengis.parameter.ParameterDescriptor;
import org.opengis.parameter.ParameterValueGroup;
// Geotools dependencies
import org.geotools.factory.Hints;
import org.geotools.coverage.grid.GridCoverage2D;
import org.geotools.coverage.grid.Interpolator2D;
import org.geotools.coverage.processing.Operation2D;
import org.geotools.metadata.iso.citation.Citations;
import org.geotools.parameter.DefaultParameterDescriptor;
import org.geotools.parameter.DefaultParameterDescriptorGroup;
import org.geotools.resources.image.ImageUtilities;
/**
* Specifies the interpolation type to be used to interpolate values for points which fall between
* grid cells. The default value is nearest neighbor. The new interpolation type operates on all
* sample dimensions. Possible values for type are: {@code "NearestNeighbor"}, {@code "Bilinear"}
* and {@code "Bicubic"} (the {@code "Optimal"} interpolation type is currently not supported).
* <p>
* <strong>Geotools extension:</strong><br>
* The Geotools implementation provides two extensions to OpenGIS specification: First, it accepts
* also an {@link javax.media.jai.Interpolation} argument type, for interoperability with
* <A HREF="http://java.sun.com/products/java-media/jai/">Java Advanced Imaging</A>. Second, it
* accepts also an array of {@link java.lang.String} or {@link javax.media.jai.Interpolation}
* objects. When an array is specified, the first interpolation in the array is applied. If this
* interpolation returns a {@code NaN} value, then the second interpolation is tried as a fallback.
* If the second interpolation returns also a {@code NaN} value, then the third one is tried and so
* on until an interpolation returns a real number or until we reach the end of interpolation list.
* This behavior is convenient when processing remote sensing images of geophysics data, for example
* <cite>Sea Surface Temperature</cite> (SST), in which clouds may mask many pixels (i.e. set them
* to some {@code NaN} values). Because {@code "Bicubic"} interpolation needs 4×4 pixels while
* {@code "Bilinear"} interpolation needs only 2x2 pixels, the {@code "Bilinear"} interpolation is
* less likely to fails because of clouds ({@code NaN} values) than the {@code "Bicubic"} one
* (note: only one {@code NaN} value is enough to make an interpolation fails). One can workaround
* the problem by trying a bicubic interpolation first, then a linear interpolation if
* {@code "Bicubic"} failed at a particular location, <cite>etc.</cite> This behavior can be
* specified with the following {@code "Type"} argument:
* <code>new String[]{"Bicubic", "Bilinear", "NearestNeighbor"}</code>.
*
* <P><STRONG>Name:</STRONG> <CODE>"Interpolate"</CODE><BR>
* <STRONG>JAI operator:</STRONG> N/A<BR>
* <STRONG>Parameters:</STRONG></P>
* <table border='3' cellpadding='6' bgcolor='F4F8FF'>
* <tr bgcolor='#B9DCFF'>
* <th>Name</th>
* <th>Class</th>
* <th>Default value</th>
* <th>Minimum value</th>
* <th>Maximum value</th>
* </tr>
* <tr>
* <td>{@code "Source"}</td>
* <td>{@link org.geotools.coverage.grid.GridCoverage2D}</td>
* <td align="center">N/A</td>
* <td align="center">N/A</td>
* <td align="center">N/A</td>
* </tr>
* <tr>
* <td>{@code "Type"}</td>
* <td>{@link java.lang.CharSequence}</td>
* <td>"NearestNeighbor"</td>
* <td align="center">N/A</td>
* <td align="center">N/A</td>
* </tr>
* </table>
*
* @since 2.2
*
* @source $URL$
* @version $Id$
* @author Martin Desruisseaux (IRD)
*
* @see org.geotools.coverage.processing.Operations#interpolate
* @see Interpolator2D
*/
public class Interpolate extends Operation2D {
/**
* Serial number for interoperability with different versions.
*/
private static final long serialVersionUID = 6742127682733620661L;
/**
* The parameter descriptor for the interpolation type.
*/
public static final ParameterDescriptor TYPE =
new DefaultParameterDescriptor(Citations.OGC, "Type",
Object.class, // Value class (mandatory)
null, // Array of valid values
"NearestNeighbor", // Default value
null, // Minimal value
null, // Maximal value
null, // Unit of measure
true); // Parameter is mandatory
/**
* Constructs an {@code "Interpolate"} operation.
*/
public Interpolate() {
super(new DefaultParameterDescriptorGroup(Citations.OGC, "Interpolate",
new ParameterDescriptor[] {
SOURCE_0,
TYPE
}));
}
/**
* Applies an interpolation to a grid coverage. This method is invoked
* by {@link org.geotools.coverage.processing.DefaultProcessor} for the
* {@code "Interpolate"} operation.
*/
public Coverage doOperation(final ParameterValueGroup parameters, final Hints hints) {
final GridCoverage2D source = (GridCoverage2D)parameters.parameter("Source").getValue();
final Object type = parameters.parameter("Type" ).getValue();
final Interpolation[] interpolations;
if (type.getClass().isArray()) {
interpolations = new Interpolation[Array.getLength(type)];
for (int i=0; i<interpolations.length; i++) {
interpolations[i] = ImageUtilities.toInterpolation(Array.get(type, i));
}
} else {
interpolations = new Interpolation[] {ImageUtilities.toInterpolation(type)};
}
return Interpolator2D.create(source, interpolations);
}
}