NCEPLIBS-w3emc  2.9.3
w3fb03.f
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1 C> @file
2 C> @brief Convert i,j grid coordinates to lat/lon.
3 C> @author Ralph Jones @date 1986-07-17
4 
5 C> Converts i,j grid coordinates to the corresponding
6 C> latitude/longitude on a southern hemisphere polar stereographic
7 C> map projection.
8 C>
9 C> Program history log.
10 C> - Ralph Jones 1986-07-17 Convert to fortran 77.
11 C> - Ralph Jones 1990-08-31 Convert to cray cft77 fortran.
12 C>
13 C> @param[in] XI Real i coordinate.
14 C> @param[in] XJ Real j coordinate.
15 C> @param[in] XMESHL Real grid interval in km.
16 C> @param[out] TLAT Real s.h. latitude.
17 C> @param[out] TLONG Real longitude.
18 C>
19 C> @author Ralph Jones @date 1986-07-17
20  SUBROUTINE w3fb03(XI, XJ, XMESHL, TLAT, TLONG)
21 C
22 C ...GIVEN ... XI/XJ GRID COORDINATES OF A POINT RELATIVE
23 C ... TO (0,0) AT SOUTH POLE
24 C ...TO COMPUTE TLAT,TLONG ON THE SRN HEMI POLAR STEREO PROJECTION
25 C ...WITH 80W VERTICAL AT TOP OF THE MAP
26 C
27  DATA degprd/57.2957795/
28  DATA earthr/6371.2/
29 C
30  re = (earthr * 1.86603) / xmeshl
31  gi2 = re * re
32 C
33 C ...WHERE GI2 IS THE SQUARE OF DISTANCE IN GRID INTERVALS
34 C ... FROM POLE TO EQUATOR...
35 C
36  r2 = xi * xi + xj * xj
37  IF (r2 .NE. 0.0) THEN
38 C
39  xlong = degprd * atan2(xj,xi)
40  tlong = xlong - 10.0
41  IF (tlong .LT. 0.0) tlong = tlong + 360.0
42  tlat = asin((gi2 - r2)/(gi2 + r2)) * degprd
43  tlat = -tlat
44 C
45  ELSE
46  tlat = -90.0
47 C
48 C ...FOR SOUTH POLE...
49 C
50  tlong = 0.0
51  ENDIF
52 C
53  RETURN
54  END
w3fb03
subroutine w3fb03(XI, XJ, XMESHL, TLAT, TLONG)
Converts i,j grid coordinates to the corresponding latitude/longitude on a southern hemisphere polar ...
Definition: w3fb03.f:21