001 //$HeadURL: $
002 /*---------------- FILE HEADER ------------------------------------------
003 This file is part of deegree.
004 Copyright (C) 2001-2008 by:
005 Department of Geography, University of Bonn
006 http://www.giub.uni-bonn.de/deegree/
007 lat/lon GmbH
008 http://www.lat-lon.de
009
010 This library is free software; you can redistribute it and/or
011 modify it under the terms of the GNU Lesser General Public
012 License as published by the Free Software Foundation; either
013 version 2.1 of the License, or (at your option) any later version.
014 This library is distributed in the hope that it will be useful,
015 but WITHOUT ANY WARRANTY; without even the implied warranty of
016 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
017 Lesser General Public License for more details.
018 You should have received a copy of the GNU Lesser General Public
019 License along with this library; if not, write to the Free Software
020 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
021 Contact:
022
023 Andreas Poth
024 lat/lon GmbH
025 Aennchenstr. 19
026 53177 Bonn
027 Germany
028 E-Mail: poth@lat-lon.de
029
030 Prof. Dr. Klaus Greve
031 Department of Geography
032 University of Bonn
033 Meckenheimer Allee 166
034 53115 Bonn
035 Germany
036 E-Mail: greve@giub.uni-bonn.de
037 ---------------------------------------------------------------------------*/
038
039 package org.deegree.crs.projections.azimuthal;
040
041 import javax.vecmath.Point2d;
042
043 import org.deegree.crs.components.Unit;
044 import org.deegree.crs.coordinatesystems.GeographicCRS;
045 import org.deegree.crs.projections.ProjectionUtils;
046 import org.deegree.crs.projections.Projection;
047
048 /**
049 * The <code>AzimuthalProjection</code> class functions as a super class to all azimuthal projections.
050 * <p>
051 * (From wikipedia) Azimuthal projections have the property that directions from a central point are preserved (and
052 * hence, great circles through the central point are represented by straight lines on the map). Usually these
053 * projections also have radial symmetry in the scales and hence in the distortions: map distances from the central
054 * point are computed by a function r(d) of the true distance d, independent of the angle; correspondingly, circles with
055 * the central point as center are mapped into circles which have as center the central point on the map.
056 * </p>
057 *
058 * <p>
059 * The mapping of radial lines can be visualized by imagining a plane tangent to the Earth, with the central point as
060 * tangent point.
061 * </p>
062 *
063 * @author <a href="mailto:bezema@lat-lon.de">Rutger Bezema</a>
064 *
065 * @author last edited by: $Author:$
066 *
067 * @version $Revision:$, $Date:$
068 *
069 */
070
071 public abstract class AzimuthalProjection extends Projection {
072
073 /**
074 * Defining that the center of this azimuthal projection is at the north pole
075 */
076 public final static int NORTH_POLE = 0;
077
078 /**
079 * Defining that the center of this azimuthal projection is at the south pole
080 */
081 public final static int SOUTH_POLE = 1;
082
083 /**
084 * Defining that the center of this azimuthal projection is at the equator
085 */
086 public final static int EQUATOR = 2;
087
088 /**
089 * Defining that the center of this azimuthal projection is oblique
090 */
091 public final static int OBLIQUE = 3;
092
093 private int mode;
094
095 /**
096 * @param geographicCRS
097 * @param falseNorthing
098 * @param falseEasting
099 * @param naturalOrigin
100 * @param units
101 * @param scale
102 * @param conformal
103 * @param equalArea
104 * @param identifiers
105 * @param names
106 * @param versions
107 * @param descriptions
108 * @param areasOfUse
109 */
110 public AzimuthalProjection( GeographicCRS geographicCRS, double falseNorthing, double falseEasting,
111 Point2d naturalOrigin, Unit units, double scale, boolean conformal, boolean equalArea, String[] identifiers,
112 String[] names, String[] versions, String[] descriptions, String[] areasOfUse ) {
113 super( geographicCRS,
114 falseNorthing,
115 falseEasting,
116 naturalOrigin,
117 units,
118 scale,
119 conformal,
120 equalArea,
121 identifiers,
122 names,
123 versions,
124 descriptions,
125 areasOfUse );
126 if ( Math.abs( Math.abs( getProjectionLatitude() ) - ProjectionUtils.HALFPI ) < ProjectionUtils.EPS10 ) {
127 mode = getProjectionLatitude() < 0. ? SOUTH_POLE : NORTH_POLE;
128 } else if ( Math.abs( getProjectionLatitude() ) > ProjectionUtils.EPS10 ) {
129 mode = OBLIQUE;
130 } else {
131 mode = EQUATOR;
132 }
133 }
134
135 /**
136 * @return the mode.
137 */
138 public final int getMode() {
139 return mode;
140 }
141
142 /**
143 * Implementation as proposed by Joshua Block in Effective Java (Addison-Wesley 2001), which supplies an even
144 * distribution and is relatively fast. It is created from field <b>f</b> as follows:
145 * <ul>
146 * <li>boolean -- code = (f ? 0 : 1)</li>
147 * <li>byte, char, short, int -- code = (int)f </li>
148 * <li>long -- code = (int)(f ^ (f >>>32))</li>
149 * <li>float -- code = Float.floatToIntBits(f);</li>
150 * <li>double -- long l = Double.doubleToLongBits(f); code = (int)(l ^ (l >>> 32))</li>
151 * <li>all Objects, (where equals( ) calls equals( ) for this field) -- code = f.hashCode( )</li>
152 * <li>Array -- Apply above rules to each element</li>
153 * </ul>
154 * <p>
155 * Combining the hash code(s) computed above: result = 37 * result + code;
156 * </p>
157 *
158 * @return (int) ( result >>> 32 ) ^ (int) result;
159 *
160 * @see java.lang.Object#hashCode()
161 */
162 @Override
163 public int hashCode() {
164 // the 2nd millionth prime, :-)
165 long code = 32452843;
166 code = code * 37 + super.hashCode();
167 code = code * 37 + getMode();
168 return (int) ( code >>> 32 ) ^ (int) code;
169 }
170 }