001 //$HeadURL: svn+ssh://rbezema@svn.wald.intevation.org/deegree/base/branches/2.2_testing/src/org/deegree/framework/util/MapUtils.java $
002 /*---------------- FILE HEADER ------------------------------------------
003
004 This file is part of deegree.
005 Copyright (C) 2001-2008 by:
006 EXSE, Department of Geography, University of Bonn
007 http://www.giub.uni-bonn.de/deegree/
008 lat/lon GmbH
009 http://www.lat-lon.de
010
011 This library is free software; you can redistribute it and/or
012 modify it under the terms of the GNU Lesser General Public
013 License as published by the Free Software Foundation; either
014 version 2.1 of the License, or (at your option) any later version.
015
016 This library is distributed in the hope that it will be useful,
017 but WITHOUT ANY WARRANTY; without even the implied warranty of
018 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
019 Lesser General Public License for more details.
020
021 You should have received a copy of the GNU Lesser General Public
022 License along with this library; if not, write to the Free Software
023 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
024
025 Contact:
026
027 Andreas Poth
028 lat/lon GmbH
029 Aennchenstr. 19
030 53115 Bonn
031 Germany
032 E-Mail: poth@lat-lon.de
033
034 Prof. Dr. Klaus Greve
035 Department of Geography
036 University of Bonn
037 Meckenheimer Allee 166
038 53115 Bonn
039 Germany
040 E-Mail: greve@giub.uni-bonn.de
041
042 ---------------------------------------------------------------------------*/
043 package org.deegree.framework.util;
044
045 import org.deegree.framework.log.ILogger;
046 import org.deegree.framework.log.LoggerFactory;
047 import org.deegree.i18n.Messages;
048 import org.deegree.model.crs.CRSFactory;
049 import org.deegree.model.crs.CoordinateSystem;
050 import org.deegree.model.crs.GeoTransformer;
051 import org.deegree.model.spatialschema.Envelope;
052 import org.deegree.model.spatialschema.GeometryFactory;
053 import org.deegree.model.spatialschema.Position;
054
055 /**
056 *
057 *
058 * @version $Revision: 9439 $
059 * @author <a href="mailto:poth@lat-lon.de">Andreas Poth</a>
060 * @author last edited by: $Author: rbezema $
061 *
062 * @version 1.0. $Revision: 9439 $, $Date: 2008-01-08 11:53:23 +0100 (Di, 08 Jan 2008) $
063 *
064 * @since 2.0
065 */
066 public class MapUtils {
067
068 private static ILogger LOG = LoggerFactory.getLogger( MapUtils.class );
069
070 /**
071 * The Value of sqrt(2)
072 */
073 public static final double SQRT2 = 1.4142135623730950488016887242096980785;
074
075 /**
076 * The Value of a PixelSize
077 */
078 public static final double DEFAULT_PIXEL_SIZE = 0.00028;
079
080 /**
081 * calculates the map scale (denominator) as defined in the OGC SLD 1.0.0 specification
082 *
083 * @param mapWidth
084 * map width in pixel
085 * @param mapHeight
086 * map height in pixel
087 * @param bbox
088 * bounding box of the map
089 * @param crs
090 * coordinate reference system of the map
091 * @param pixelSize
092 * size of one pixel of the map measured in meter
093 *
094 * @return a maps scale based on the diagonal size of a pixel at the center of the map in meter.
095 * @throws RuntimeException
096 */
097 public static double calcScale( int mapWidth, int mapHeight, Envelope bbox, CoordinateSystem crs, double pixelSize )
098 throws RuntimeException {
099
100 if ( mapWidth == 0 || mapHeight == 0 ) {
101 return 0;
102 }
103
104 double scale = 0;
105
106 CoordinateSystem cs = crs;
107
108 if ( cs == null ) {
109 throw new RuntimeException( "Invalid crs: " + crs );
110 }
111
112 try {
113 if ( "m".equals( cs.getUnits() ) ) {
114
115 /*
116 * this method to calculate a maps scale as defined in OGC WMS and SLD specification
117 * is not required for maps having a projected reference system. Direct calculation
118 * of scale avoids uncertaincies
119 */
120 double bboxWidth = bbox.getWidth();
121 double bboxHeight = bbox.getHeight();
122 double d1 = Math.sqrt( ( mapWidth * mapWidth ) + ( mapHeight * mapHeight ) );
123 double d2 = Math.sqrt( ( bboxWidth * bboxWidth ) + ( bboxHeight * bboxHeight ) );
124 scale = ( d2 / d1 ) / pixelSize;
125 } else {
126
127 if ( !crs.getName().equalsIgnoreCase( "EPSG:4326" ) ) {
128 // transform the bounding box of the request to EPSG:4326
129 GeoTransformer trans = new GeoTransformer( CRSFactory.create( "EPSG:4326" ) );
130 bbox = trans.transform( bbox, crs );
131 }
132 double dx = bbox.getWidth() / mapWidth;
133 double dy = bbox.getHeight() / mapHeight;
134 Position min = GeometryFactory.createPosition( bbox.getMin().getX() + dx * ( mapWidth / 2d - 1 ),
135 bbox.getMin().getY() + dy * ( mapHeight / 2d - 1 ) );
136 Position max = GeometryFactory.createPosition( bbox.getMin().getX() + dx * ( mapWidth / 2d ),
137 bbox.getMin().getY() + dy * ( mapHeight / 2d ) );
138
139 double distance = calcDistance( min.getX(), min.getY(), max.getX(), max.getY() );
140
141 scale = distance * ( SQRT2 / pixelSize );
142
143 }
144 } catch ( Exception e ) {
145 LOG.logError( e.getMessage(), e );
146 throw new RuntimeException( Messages.getMessage( "FRAMEWORK_ERROR_SCALE_CALC", e.getMessage() ) );
147 }
148
149 return scale;
150
151 }
152
153 /**
154 * calculates the distance in meters between two points in EPSG:4326 coodinates. this is a
155 * convenience method assuming the world is a ball
156 *
157 * @param lon1
158 * @param lat1
159 * @param lon2
160 * @param lat2
161 * @return the distance in meters between two points in EPSG:4326 coords
162 */
163 public static double calcDistance( double lon1, double lat1, double lon2, double lat2 ) {
164 double r = 6378.137;
165 double rad = Math.PI / 180d;
166 double cose = Math.sin( rad * lon1 ) * Math.sin( rad * lon2 ) + Math.cos( rad * lon1 ) * Math.cos( rad * lon2 )
167 * Math.cos( rad * ( lat1 - lat2 ) );
168 double dist = r * Math.acos( cose ) * Math.cos( rad * Math.min( lat1, lat2 ) );
169
170 // * 0.75 is just an heuristic correction factor
171 return dist * 1000 * 0.75;
172 }
173
174 /**
175 * The method calculates a new Envelope from the <code>requestedBarValue</code> It will either
176 * zoom in or zoom out of the <code>actualBBOX<code> depending
177 * on the ratio of the <code>requestedBarValue</code> to the <code>actualBarValue</code>
178 * @param currentEnvelope current Envelope
179 * @param currentScale the scale of the current envelope
180 * @param requestedScale requested scale value
181 * @return a new Envelope
182 */
183 public static Envelope scaleEnvelope( Envelope currentEnvelope, double currentScale, double requestedScale ) {
184
185 double ratio = requestedScale / currentScale;
186 double newWidth = currentEnvelope.getWidth() * ratio;
187 double newHeight = currentEnvelope.getHeight() * ratio;
188 double midX = currentEnvelope.getMin().getX() + ( currentEnvelope.getWidth() / 2d );
189 double midY = currentEnvelope.getMin().getY() + ( currentEnvelope.getHeight() / 2d );
190
191 double minx = midX - newWidth / 2d;
192 double maxx = midX + newWidth / 2d;
193 double miny = midY - newHeight / 2d;
194 double maxy = midY + newHeight / 2d;
195
196 return GeometryFactory.createEnvelope( minx, miny, maxx, maxy, currentEnvelope.getCoordinateSystem() );
197
198 }
199
200 /**
201 * This method ensures the bbox is resized (shrunk) to match the aspect ratio defined by
202 * mapHeight/mapWidth
203 *
204 * @param bbox
205 * @param mapWith
206 * @param mapHeight
207 * @return a new bounding box with the aspect ratio given my mapHeight/mapWidth
208 */
209 public static final Envelope ensureAspectRatio( Envelope bbox, double mapWith, double mapHeight ) {
210
211 double minx = bbox.getMin().getX();
212 double miny = bbox.getMin().getY();
213 double maxx = bbox.getMax().getX();
214 double maxy = bbox.getMax().getY();
215
216 double dx = maxx - minx;
217 double dy = maxy - miny;
218
219 double ratio = mapHeight / mapWith;
220
221 if ( dx >= dy ) {
222 // height has to be corrected
223 double[] normCoords = getNormalizedCoords( dx, ratio, miny, maxy );
224 miny = normCoords[0];
225 maxy = normCoords[1];
226 } else {
227 // width has to be corrected
228 ratio = mapWith / mapHeight;
229 double[] normCoords = getNormalizedCoords( dy, ratio, minx, maxx );
230 minx = normCoords[0];
231 maxx = normCoords[1];
232 }
233 CoordinateSystem crs = bbox.getCoordinateSystem();
234
235 return GeometryFactory.createEnvelope( minx, miny, maxx, maxy, crs );
236 }
237
238 private static final double[] getNormalizedCoords( double normLen, double ratio, double min, double max ) {
239 double mid = ( max - min ) / 2 + min;
240 min = mid - ( normLen / 2 ) * ratio;
241 max = mid + ( normLen / 2 ) * ratio;
242 double[] newCoords = { min, max };
243 return newCoords;
244 }
245
246 }