Lambert(兰勃托)投影--我国天气图底图广泛采用的一种投影

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Lambert.java

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001 /**
002 
003   Lambert兰勃特投影
004 
005      PACKAGE: cma.common.projection
006     FILENAME: Lambert.java
007     LANGUAGE: Java2 v1.4
008     ORIGINAL: 最初由成气院向卫国袁东升老师编写，但与Micaps1.0的兰勃特投影不一致，距离标准经度远的地方误差增大。
009  DESCRIPTION: Lambert projection coordinate
010       CREATE: 2003-03-06 00:31:21
011       UPDATE: 2007-07-17 根据 http://mathworld.wolfram.com  提供的公式重新编写
012       AUTHOR: 刘泽军 ([email protected])
013               广西气象减灾研究所
014               Guangxi Institude of Meteorology and Disaster-reducing Research(GIMDR)
015    REFERENCE: http://mathworld.wolfram.com/LambertConformalConicProjection.html
016 
017      COMPILE: javac Coordinate.java Lambert.java
018 
019 ********** 重写后，与Micaps1.0版的“T-兰勃脱投影”完全一致！ **********
020 
021      HISTORY:
022         0、lbt.cpp，两位老师的源代码
023         1、CCoordinate.cpp，线性和Lambert投影，主要用于FY-2B卫星云图定位和Micaps交互；
024         2、CRotateCoordinate.cpp，坐标旋转，主要是用于柳州Doppler雷达选址时从扫描的军用地图中定位及读取高程信息)；
025         3、CLambert.cpp、CLines.cpp，各投影代码独立为类
026         4、Lambert.java，兰勃托投影改写为JAVA版
027         5、Lambert.java，2007-07-17重新编写
028 
029 **/
030 
031 package cma.common.projection;
032 
033 import java.io.*;
034 import java.awt.*;
035 import java.awt.geom.*;
036 import java.util.*;
037 import java.lang.Math.*;
038 import java.text.DecimalFormat;
039 
040 import cma.common.atmos.*;
041 
042 public class Lambert extends Coordinate {
043 
044     //private   double  fn = 0.715566799999999;
045     private double  F;
046     private double  n;
047     private double  p0;
048 
049     private void reset(//Degree
050             double  standardLon,    double  standardLat,
051             double  positionLon,    double  positionLat,
052             int     positionHori,   int     positionVert,
053             double  zoomIndex) {
054         type            = Coordinate.LAMBERT;
055         standard        = new Point2D.Double(Math.IEEEremainder(Math.abs(standardLon), 360.0), 0.0);
056         center          = new Point2D.Double(Math.IEEEremainder(Math.abs(positionLon), 360.0), positionLat < -85.0 ? -85.0 : positionLat > 85.0 ? 85.0 : positionLat);
057         place           = new Point(positionHori, positionVert);
058         scale           = zoomIndex <= 0.0 ? 1.0 : zoomIndex;
059         scaleOriginal   = scale;
060 
061         double  lat1= Math.toRadians(30.0), lat2 = Math.toRadians(60.0);//标准纬度
062         double  lat3= Math.toRadians(45.0+30.0/2.0), lat4 = Math.toRadians(45.0+60.0/2);//标准纬度
063         double  lat5= Math.toRadians(45.0+center.y/2.0),  lat6 = Math.toRadians(45.0+standard.y/2.0);
064         n   = Math.log(Math.cos(lat1)/Math.cos(lat2))/Math.log(Math.tan(lat4)/Math.tan(lat3));
065         F   = scale * 484.96 * Math.cos(lat1)*Math.pow(Math.tan(lat3),n)/n;//484.96为根据Micaps1.0拟合得到的数值
066         p0  = F * Math.pow(1.0/Math.tan(lat6),n);
067         double  r   = Math.toRadians(n*(center.x-standard.x));
068         double  p   = F * Math.pow(1.0/Math.tan(lat5),n);
069         double  x   = p * Math.sin(r);
070         double  y   = p * Math.cos(r) - p0;
071         offset      = new Point((int)(0.5 + place.x - x), (int)(0.5 + place.y - y));
072     }
073 
074     public Lambert() {
075         reset(
076             110.0,  30.0,
077             110.0,  35.0,
078             512,    384,
079             1
080         );
081     }
082 
083     public Lambert(//Degree
084             double  standardLon,    double  standardLat,
085             double  positionLon,    double  positionLat,
086             int     positionHori,   int     positionVert,
087             double  zoomIndex) {
088         reset(
089             standardLon,standardLat,
090             positionLon,    positionLat,
091             positionHori,   positionVert,
092             zoomIndex
093         );
094     }
095 
096     public Lambert(//Degree
097             double  positionLon,    double  positionLat,
098             int     positionHori,   int     positionVert,
099             double  zoomIndex) {
100         reset(
101             110.0,      30.0,
102             positionLon,    positionLat,
103             positionHori,   positionVert,
104             zoomIndex
105         );
106     }
107 
108 /**
109  * 功能：获得屏幕坐标
110  * 参数：
111  *      lon     - 经度值(度)
112  *      lat     - 纬度值(度)
113  * 返回值：
114  *      屏幕坐标
115  */
116     public Point getPosition(double lon, double lat) {
117         double  lat5= Math.toRadians(45.0+lat/2.0);
118         double  r   = Math.toRadians(n*(lon-standard.x));
119         double  p   = F * Math.pow(1.0/Math.tan(lat5),n);
120         double  x   = p * Math.sin(r);
121         double  y   = p * Math.cos(r) - p0;
122         return(new Point((int)(0.5 + offset.x + x), (int)(0.5 + offset.y + y)));
123     }
124 
125 /**
126  * 功能：获得经纬度坐标
127  * 参数：
128  *  xScreen     - 屏幕坐标值(x方向)
129  *  yScreen     - 屏幕坐标值(y方向)
130  * 返回值：
131  *      经纬度坐标
132  */
133     public Point2D.Double getCoordinate(int x, int y) {
134 
135         double  lon, lat, r;
136         if( y-offset.y+p0 == 0 ) {
137             lon = standard.x+45.0/n;
138             lat = 2.0*(Math.toDegrees(Math.atan(1.0/Math.pow((x-offset.x)/F,1.0/n)))-45.0);
139         }
140         else {
141             lon = standard.x + Math.toDegrees(Math.atan((x-offset.x)/(y-offset.y+p0)))/n;
142             r   = Math.toRadians(n*(lon-standard.x));
143             lat = 2.0*(Math.toDegrees(Math.atan(1.0/Math.pow((y-offset.y+p0)/Math.cos(r)/F,1.0/n)))-45.0);
144         }
145         return(new Point2D.Double(lon,lat));
146     }
147 
148 /**
149  * 功能：获得相对于标准经度的偏角
150  * 参数：
151  *  degreeLon   - 经度值
152  *  degreeLat   - 纬度值
153  * 返回值：
154  *      偏角
155  */
156     public double getAngle(double degreeLon, double degreeLat) {
157         if( 9999.0 <= degreeLat || -9999.0 >= degreeLat || 90.0 == degreeLat || -90.0 == degreeLat ) {
158             return(0.0);
159         }
160         Point   xy1     = getPosition(standard.x, 90.0);
161         Point   xy2     = getPosition(degreeLon, degreeLat);
162         double  x1      = xy1.x;
163         double  y1      = xy1.y;
164         double  x2      = xy2.x;
165         double  y2      = xy2.y;
166         double  rotateAngle = 0.0;
167         if( x2 == x1 ) {
168             rotateAngle = y2 >= y1 ? 0.0 : 180.0;
169         }
170         else if( y1 == y2 ) {
171             rotateAngle = x2 >= x1 ? 270.0 : 90.0;
172         }
173         else {//分象限判断旋转角度，坐标原点在xy1
174             double  deltaY      = Math.abs(y2 - y1);
175             double  r           = Math.sqrt((x2 - x1)*(x2 - x1) + (y2 - y1)*(y2 - y1));
176             double  angelDegree = Math.toDegrees(Math.asin(deltaY/r));
177             if( x2 > x1 && y2 > y1 ) {
178                 rotateAngle = -90.0 + angelDegree;
179             }
180             else if( x2 > x1 && y2 < y1 ) {
181                 rotateAngle = -90.0 - angelDegree;
182             }
183             else if( x2 < x1 && y2 < y1 ) {
184                 rotateAngle = 90.0 + angelDegree;
185             }
186             else if( x2 < x1 && y2 > y1 ) {
187                 rotateAngle = 90.0 - angelDegree;
188             }
189             else {
190                 return(Algorithm.DefaultValue);
191             }
192         }
193         return(rotateAngle);
194     }
195 
196 /**
197  * 功能：
198  *      画经线、纬线
199  * 参数：
200  *      g       - 图形设备
201  *      f       - 字体
202  *      c       - 画线颜色
203  *      inc_lon - 经线间隔
204  *      inc_lat - 纬线间隔
205  * 返回值：
206  *      无
207  */
208     public void drawGridLine(Graphics2D g, Font f, Color c, int inc_lon, int inc_lat) {
209 
210         DecimalFormat   df  = new DecimalFormat("0.#");
211         Color   saveColor   = g.getColor();
212         Font    saveFont    = g.getFont();
213         g.setColor(c);
214         g.setFont(null==f?f:new Font("Times New Roman", Font.PLAIN, 12));
215         Point       xy, xy1;
216         double      rotateAngle;
217         FontMetrics fm  = g.getFontMetrics();
218         String      text;
219         byte        tmpByte[];
220         int         bytesWidth, bytesHeight = fm.getHeight();;
221         g.setColor(c);
222         Point   pos1, pos2;
223         //画纬线
224         for(int lat=80;lat>=-80+inc_lat;lat=lat-inc_lat) {
225             for(int lon=0;lon<360;lon++) {
226                 pos1    = getPosition(lon, lat);
227                 pos2    = getPosition(lon+1, lat);
228                 g.drawLine(pos1.x, pos1.y, pos2.x, pos2.y);
229                 if( lon % 90 == 0 ) {
230                     g.translate(pos1.x, pos1.y);
231                     rotateAngle = getAngle(lon, lat);
232                     if( rotateAngle != Algorithm.DefaultValue ) {
233                         g.rotate(Math.toRadians(rotateAngle));  //偏角
234                     }
235                     text        = df.format(lat);
236                     tmpByte     = text.getBytes();
237                     bytesWidth  = fm.bytesWidth(tmpByte, 0, tmpByte.length);
238                     g.drawString(text, -bytesWidth/2, bytesHeight/3);//标纬度值
239                     if( rotateAngle != Algorithm.DefaultValue ) {
240                         g.rotate(Math.toRadians(-rotateAngle)); //偏角
241                     }
242                     g.translate(-pos1.x, -pos1.y);
243                 }
244             }
245         }
246         //画经线
247         for(int lon=0;lon<=360;lon=lon+inc_lon) {
248             pos1    = getPosition(lon,  80.0);
249             pos2    = getPosition(lon, -80.0);
250             g.drawLine(pos1.x, pos1.y, pos2.x, pos2.y);
251             pos1    = getPosition(lon,   0.0);
252             g.translate(pos1.x, pos1.y);
253             rotateAngle = getAngle(lon, 0.0);
254             if( rotateAngle != Algorithm.DefaultValue ) {
255                 g.rotate(Math.toRadians(rotateAngle));  //偏角
256             }
257             text        = df.format(lon);
258             tmpByte     = text.getBytes();
259             bytesWidth  = fm.bytesWidth(tmpByte, 0, tmpByte.length);
260             g.drawString(text, -bytesWidth/2, bytesHeight/3);//标纬度值
261             if( rotateAngle != Algorithm.DefaultValue ) {
262                 g.rotate(Math.toRadians(-rotateAngle)); //偏角
263             }
264             g.translate(-pos1.x, -pos1.y);
265         }
266         g.setFont(saveFont);
267         g.setColor(saveColor);
268     }
269 }