/*
* GeoTools - The Open Source Java GIS Toolkit
* http://geotools.org
*
* (C) 2005-2008, 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;
// JAI dependencies (for javadoc)
import javax.media.jai.operator.LogDescriptor;
// Geotools dependencies
import org.geotools.util.NumberRange;
import org.geotools.coverage.processing.OperationJAI;
/**
* Takes the natural logarithm of the sample values of a coverage.
*
* <P><STRONG>Name:</STRONG> <CODE>"Log"</CODE><BR>
* <STRONG>JAI operator:</STRONG> <CODE>"{@linkplain LogDescriptor Log}"</CODE><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>
* </table>
*
* @since 2.2
*
*
* @source $URL$
* @version $Id$
* @author Martin Desruisseaux (IRD)
*
* @see org.geotools.coverage.processing.Operations#log
* @see LogDescriptor
*/
public class Log extends OperationJAI {
/**
* Serial number for interoperability with different versions.
*/
private static final long serialVersionUID = -3622176942444895367L;
/**
* Constructs a default {@code "Log"} operation.
*/
public Log() {
super("Log");
}
/**
* Returns the expected range of values for the resulting image.
*/
protected NumberRange deriveRange(final NumberRange[] ranges, final Parameters parameters) {
final NumberRange range = ranges[0];
final double min = Math.log(range.getMinimum());
final double max = Math.log(range.getMaximum());
return NumberRange.create(min, max);
}
}