/*
 *    GeoTools - OpenSource mapping toolkit
 *    http://geotools.org
 *    (C) 2004-2006, GeoTools Project Managment Committee (PMC)
 *   
 *    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.referencing.factory.wms;

// OpenGIS dependencies
import org.opengis.parameter.ParameterValueGroup;


/**
 * Auto Universal Transverse Mercator ({@code AUTO:42001}).
 * In the notation below, "<code>${var}</code>" denotes a reference to the value of a variable
 * "{@code var}". The variables "{@code lat0}" and "{@code lon0}" are the central point of the
 * projection appearing in the CRS parameter of the map request. The coordinate operation method
 * uses ellipsoidal formulas.
 *
 * <pre>
 * PROJCS["WGS 84 / Auto UTM",
 *   GEOGCS["WGS 84",
 *     DATUM["WGS_1984",
 *       SPHEROID["WGS_1984", 6378137, 298.257223563]],
 *     PRIMEM["Greenwich", 0],
 *     UNIT["Decimal_Degree", 0.0174532925199433]],
 *   PROJECTION["Transverse_Mercator"],
 *   PARAMETER["Latitude_of_Origin", 0],
 *   PARAMETER["Central_Meridian", ${central_meridian}],
 *   PARAMETER["False_Easting", 500000],
 *   PARAMETER["False_Northing", ${false_northing}],
 *   PARAMETER["Scale_Factor", 0.9996],
 *   UNIT["Meter", 1]]
 * </pre>
 *
 * Where:
 *
 * <pre>
 * ${zone}             = min( floor( (${lon0} + 180.0) / 6.0 ) + 1, 60 )
 * ${central_meridian} = -183.0 + ${zone} * 6.0
 * ${false_northing}   = (${lat0} >= 0.0) ? 0.0 : 10000000.0
 * </pre>
 *
 * @source $URL: http://svn.geotools.org/geotools/tags/2.4.1/modules/library/referencing/src/main/java/org/geotools/referencing/factory/wms/Auto42001.java $
 * @version $Id: Auto42001.java 20874 2006-08-07 10:00:01Z jgarnett $
 * @author Jody Garnett
 * @author Rueben Schulz
 * @author Martin Desruisseaux
 */
final class Auto42001 extends Factlet {
    /**
     * A shared (thread-safe) instance.
     */
    public static final Auto42001 DEFAULT = new Auto42001();

    /**
     * Do not allows instantiation except the {@link #DEFAULT} constant.
     */
    private Auto42001() {
    }

    /**
     * {@inheritDoc}
     */
    public int code() {
        return 42001;
    }

    /**
     * {@inheritDoc}
     */
    public String getName() {
        return "WGS 84 / Auto UTM";
    }

    /**
     * {@inheritDoc}
     */
    public String getClassification() {
        return "Transverse_Mercator";
    }

    /**
     * {@inheritDoc}
     */
    protected void setProjectionParameters(final ParameterValueGroup parameters, final Code code) {
        final double   zone            = Math.min(Math.floor((code.longitude + 180.0)/6.0)+1, 60);
        final double   centralMeridian = -183.0 + zone*6.0;
        final double   falseNorthing   = code.latitude >= 0.0 ? 0.0 : 10000000.0;

        parameters.parameter("latitude_of_origin").setValue(0.0);
        parameters.parameter("central_meridian")  .setValue(centralMeridian);
        parameters.parameter("false_easting")     .setValue(500000.0);
        parameters.parameter("false_northing")    .setValue(falseNorthing);
        parameters.parameter("scale_factor")      .setValue(0.9996);
    }
}
