001 //$HeadURL: https://svn.wald.intevation.org/svn/deegree/base/branches/2.3_testing/src/org/deegree/crs/projections/azimuthal/AzimuthalProjection.java $
002 /*----------------------------------------------------------------------------
003 This file is part of deegree, http://deegree.org/
004 Copyright (C) 2001-2009 by:
005 Department of Geography, University of Bonn
006 and
007 lat/lon GmbH
008
009 This library is free software; you can redistribute it and/or modify it under
010 the terms of the GNU Lesser General Public License as published by the Free
011 Software Foundation; either version 2.1 of the License, or (at your option)
012 any later version.
013 This library is distributed in the hope that it will be useful, but WITHOUT
014 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
015 FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
016 details.
017 You should have received a copy of the GNU Lesser General Public License
018 along with this library; if not, write to the Free Software Foundation, Inc.,
019 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
020
021 Contact information:
022
023 lat/lon GmbH
024 Aennchenstr. 19, 53177 Bonn
025 Germany
026 http://lat-lon.de/
027
028 Department of Geography, University of Bonn
029 Prof. Dr. Klaus Greve
030 Postfach 1147, 53001 Bonn
031 Germany
032 http://www.geographie.uni-bonn.de/deegree/
033
034 e-mail: info@deegree.org
035 ----------------------------------------------------------------------------*/
036
037 package org.deegree.crs.projections.azimuthal;
038
039 import static org.deegree.crs.projections.ProjectionUtils.EPS10;
040 import static org.deegree.crs.projections.ProjectionUtils.HALFPI;
041
042 import javax.vecmath.Point2d;
043
044 import org.deegree.crs.Identifiable;
045 import org.deegree.crs.components.Unit;
046 import org.deegree.crs.coordinatesystems.GeographicCRS;
047 import org.deegree.crs.projections.Projection;
048
049 /**
050 * The <code>AzimuthalProjection</code> class functions as a super class to all azimuthal projections.
051 * <p>
052 * (From wikipedia) Azimuthal projections have the property that directions from a central point are preserved (and
053 * hence, great circles through the central point are represented by straight lines on the map). Usually these
054 * projections also have radial symmetry in the scales and hence in the distortions: map distances from the central
055 * point are computed by a function r(d) of the true distance d, independent of the angle; correspondingly, circles with
056 * the central point as center are mapped into circles which have as center the central point on the map.
057 * </p>
058 *
059 * <p>
060 * The mapping of radial lines can be visualized by imagining a plane tangent to the Earth, with the central point as
061 * tangent point.
062 * </p>
063 *
064 * @author <a href="mailto:bezema@lat-lon.de">Rutger Bezema</a>
065 *
066 * @author last edited by: $Author: mschneider $
067 *
068 * @version $Revision: 18195 $, $Date: 2009-06-18 17:55:39 +0200 (Do, 18. Jun 2009) $
069 *
070 */
071
072 public abstract class AzimuthalProjection extends Projection {
073
074 private static final long serialVersionUID = -8316492116621029077L;
075
076 /**
077 * Defining that the center of this azimuthal projection is at the north pole
078 */
079 public final static int NORTH_POLE = 0;
080
081 /**
082 * Defining that the center of this azimuthal projection is at the south pole
083 */
084 public final static int SOUTH_POLE = 1;
085
086 /**
087 * Defining that the center of this azimuthal projection is at the equator
088 */
089 public final static int EQUATOR = 2;
090
091 /**
092 * Defining that the center of this azimuthal projection is oblique
093 */
094 public final static int OBLIQUE = 3;
095
096 private int mode;
097
098 /**
099 * @param geographicCRS
100 * @param falseNorthing
101 * @param falseEasting
102 * @param naturalOrigin
103 * @param units
104 * @param scale
105 * @param conformal
106 * @param equalArea
107 * @param id
108 * an identifiable instance containing information about this projection
109 */
110 public AzimuthalProjection( GeographicCRS geographicCRS, double falseNorthing, double falseEasting,
111 Point2d naturalOrigin, Unit units, double scale, boolean conformal, boolean equalArea,
112 Identifiable id ) {
113 super( geographicCRS, falseNorthing, falseEasting, naturalOrigin, units, scale, conformal, equalArea, id );
114 if ( Math.abs( Math.abs( getProjectionLatitude() ) - HALFPI ) < EPS10 ) {
115 mode = getProjectionLatitude() < 0. ? SOUTH_POLE : NORTH_POLE;
116 } else if ( Math.abs( getProjectionLatitude() ) > EPS10 ) {
117 mode = OBLIQUE;
118 } else {
119 mode = EQUATOR;
120 }
121 }
122
123 /**
124 * @return the mode.
125 */
126 public final int getMode() {
127 return mode;
128 }
129
130 /**
131 * Implementation as proposed by Joshua Block in Effective Java (Addison-Wesley 2001), which supplies an even
132 * distribution and is relatively fast. It is created from field <b>f</b> as follows:
133 * <ul>
134 * <li>boolean -- code = (f ? 0 : 1)</li>
135 * <li>byte, char, short, int -- code = (int)f</li>
136 * <li>long -- code = (int)(f ^ (f >>>32))</li>
137 * <li>float -- code = Float.floatToIntBits(f);</li>
138 * <li>double -- long l = Double.doubleToLongBits(f); code = (int)(l ^ (l >>> 32))</li>
139 * <li>all Objects, (where equals( ) calls equals( ) for this field) -- code = f.hashCode( )</li>
140 * <li>Array -- Apply above rules to each element</li>
141 * </ul>
142 * <p>
143 * Combining the hash code(s) computed above: result = 37 * result + code;
144 * </p>
145 *
146 * @return (int) ( result >>> 32 ) ^ (int) result;
147 *
148 * @see java.lang.Object#hashCode()
149 */
150 @Override
151 public int hashCode() {
152 // the 2nd millionth prime, :-)
153 long code = 32452843;
154 code = code * 37 + super.hashCode();
155 code = code * 37 + getMode();
156 return (int) ( code >>> 32 ) ^ (int) code;
157 }
158 }