1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253
|
C Copyright 1981-2007 ECMWF
C
C Licensed under the GNU Lesser General Public License which
C incorporates the terms and conditions of version 3 of the GNU
C General Public License.
C See LICENSE and gpl-3.0.txt for details.
C
INTEGER FUNCTION HGENGRD(AREA,POLE,GRID,NLON,NLAT,RLAT,RLON)
C
C---->
C**** HWTS12
C
C Purpose
C -------
C
C This routine calculates the original latitude and longitude
C values (before rotation) for a rotated grid.
C
C
C Interface
C ---------
C
C IRET = HGENGRD(AREA,POLE,GRID,NLON,NLAT,RLAT,RLON)
C
C
C Input parameters
C ----------------
C
C AREA - Limits of area (N/W/S/E)
C POLE - Pole of rotation (lat/long)
C GRID - Grid increments (i/j)
C
C
C Output parameters
C -----------------
C
C NLON - Number of points along a parallel in the rotated grid.
C NLAT - Number of points along a meridien in the rotated grid.
C RLAT - Vector of orginal latitude values for the points in
C the rotated grid.
C RLON - Vector of orginal longitude values for the points in
C the rotated grid.
C
C Returns 0 if function successful, non-zero otherwise.
C
C Common block usage
C ------------------
C
C None.
C
C
C Method
C ------
C
C The vector of points runs from West to East in rows, the rows
C run from North to South.
C
C
C Externals
C ---------
C
C INTLOG - Log error message.
C JDEBUG - Tests if debug output required.
C HLL2XYZ - Converts a latitude/longitude position to (x,y,z)
C wrt axes through the centre of the globe. The z-axis
C runs from the south to north pole. The x- and y-axes
C are in the plane of the equator with the x-axis
C pointing out through lat/long (0,0).
C YROTATE - Rotates the globe about the new y-axis.
C XYZ2LL - Converts an (x,y,z) position to a latitude/longitude.
C JMALLOC - Dynamically allocate memory
C JFREE - Free dynamically allocated memory
C
C
C Reference
C ---------
C
C None.
C
C
C Comments
C --------
C
C None.
C
C
C Author
C ------
C
C J.D.Chambers ECMWF January 2001
C
C
C Modifications
C -------------
C
C None.
C
C----<
C -----------------------------------------------------------------|
C* Section 0. Definition of variables.
C -----------------------------------------------------------------|
C
IMPLICIT NONE
#include "parim.h"
C
C Parameters
C
INTEGER JNORTH, JSOUTH, JWEST, JEAST, JW_E, JN_S, JLAT, JLON
REAL JSCALE
PARAMETER (JNORTH = 1 )
PARAMETER (JWEST = 2 )
PARAMETER (JSOUTH = 3 )
PARAMETER (JEAST = 4 )
PARAMETER (JW_E = 1 )
PARAMETER (JN_S = 2 )
PARAMETER (JLAT = 1 )
PARAMETER (JLON = 2 )
PARAMETER (JSCALE = 1000.0 )
C
C Function arguments
C
REAL AREA(4),POLE(2),GRID(2), RLAT(*),RLON(*)
INTEGER NLON,NLAT
C
C Local variables
C
INTEGER NEXT, LOOP, LOOPI, LOOPO, IGRIDNI, IGRIDNJ
INTEGER ISIZE, ISIZOLD, NBYTES
REAL ZLAT, X(1), Y(1), Z(1)
REAL RX(1), RY(1), RZ(1)
POINTER( IPX, X )
POINTER( IPY, Y )
POINTER( IPZ, Z )
POINTER( IPRX, RX )
POINTER( IPRY, RY )
POINTER( IPRZ, RZ )
C
DATA ISIZOLD/-1/
SAVE ISIZOLD,IPX,IPY,IPZ,IPRX,IPRY,IPRZ
C
C Externals
C
#ifdef POINTER_64
INTEGER*8 JMALLOC
#else
INTEGER JMALLOC
#endif
C
C -----------------------------------------------------------------|
C Section 1. Initialise.
C -----------------------------------------------------------------|
C
100 CONTINUE
C
HGENGRD = 0
C
CALL JDEBUG()
C
C -----------------------------------------------------------------|
C Section 2. Calculate current grid latitudes and longitudes
C -----------------------------------------------------------------|
C
200 CONTINUE
C
NLON = 1 + NINT((AREA(JEAST) - AREA(JWEST)) / GRID(JW_E))
NLAT = 1 + NINT((AREA(JNORTH) - AREA(JSOUTH)) / GRID(JN_S))
IGRIDNI = NINT(GRID(JW_E)*JSCALE)
IGRIDNJ = NINT(GRID(JN_S)*JSCALE)
C
NEXT = 1
DO LOOPO = 1, NLAT
ZLAT = AREA(JNORTH) - REAL((LOOPO-1)*IGRIDNJ)/JSCALE
DO LOOPI = 1, NLON
RLON(NEXT) = AREA(JWEST) + REAL((LOOPI-1)*IGRIDNI)/JSCALE
IF( RLON(NEXT).LT.0.0 ) RLON(NEXT) = RLON(NEXT) + 360.0
RLAT(NEXT) = ZLAT
NEXT = NEXT + 1
ENDDO
ENDDO
C
C -----------------------------------------------------------------|
C Section 3. Get some space for rotating the lat/longs
C -----------------------------------------------------------------|
C
300 CONTINUE
C
ISIZE = NLAT *NLON
IF( ISIZE.GT.ISIZOLD ) THEN
C
IF( ISIZOLD.GT.0 ) CALL JFREE(IPX)
C
NBYTES = 6*ISIZE*JPRLEN
C
IPX = JMALLOC(NBYTES)
#ifdef hpR64
IPX = IPX/(1024*1024*1024*4)
#endif
IF( IPX.EQ.0 ) THEN
CALL INTLOG(JP_WARN,'HGENGRD: Memory allocate fail',JPQUIET)
HGENGRD = 1
GOTO 900
ENDIF
C
IPY = IPX + (ISIZE*JPRLEN)
IPZ = IPY + (ISIZE*JPRLEN)
IPRX = IPZ + (ISIZE*JPRLEN)
IPRY = IPRX + (ISIZE*JPRLEN)
IPRZ = IPRY + (ISIZE*JPRLEN)
C
ISIZOLD = ISIZE
C
ENDIF
C
C -----------------------------------------------------------------|
C Section 4. Calculate the lat/longs before rotation
C -----------------------------------------------------------------|
C
400 CONTINUE
C
C Convert the rotated row points lat/longs to (x,y,z) coordinates
C
CALL HLL2XYZ(RLAT,RLON,X,Y,Z,ISIZE)
C
C Rotate the rotated row points back through the original latitude
C rotation
C
CALL YROTATE(-(90.0+POLE(JLAT)),X,Y,Z,RX,RY,RZ,ISIZE)
C
C Convert the rotated row points adjusted (x,y,z) coordinates to
C lat/long in the original grid (but still containing the
C longitude rotation)
C
CALL XYZ2LL(RX,RY,RZ,RLAT,RLON,ISIZE)
C
C Adjust the rotated line longitudes to remove the longitude
C rotation
C
DO LOOP = 1, ISIZE
RLON(LOOP) = RLON(LOOP) + POLE(JLON)
IF( RLON(LOOP).LT.0.0 ) RLON(LOOP) = RLON(LOOP) + 360.0
IF( RLON(LOOP).GE.360.0 ) RLON(LOOP) = RLON(LOOP) - 360.0
ENDDO
C
C -----------------------------------------------------------------|
C Section 9. Return
C -----------------------------------------------------------------|
C
900 CONTINUE
C
RETURN
END
|