cnvcoord.f
123 lines
| 4.8 KiB
| text/x-fortran
|
FortranFixedLexer
| r0 | SUBROUTINE CNVCOORD(IN_LAT,IN_LONG,HEIGHT,ORDER,OUT_LAT,OUT_LONG, | |||
| + OUT_R,MGFLAG,ERR) | ||||
| c | ||||
| c $Revision: 1.1 $ | ||||
| c***************************************************************** | ||||
| c Author: Kile B. Baker | ||||
| c Johns Hopkins Applied Physics Laboratory | ||||
| c***************************************************************** | ||||
| c | ||||
| c | ||||
| c This routine uses a set of coefficients from the file | ||||
| c cnvcoord.dat to perform a coordinate | ||||
| c conversion between geographic and magnetic (or visa versa) | ||||
| c coordinates. The conversion is done using a spherical | ||||
| c harmonic expansion. | ||||
| c | ||||
| c REFERENCE: Baker, K.B. and S. Wing, | ||||
| c J. Geophys. Res., Vol. 94, pg. 9139, 1989. | ||||
| c | ||||
| c********************************************************************** | ||||
| c This program and all the associated subroutines and data files | ||||
| c may be freely copied and distributed, but the Authors and the | ||||
| c Applied Physics Laboratory will not be responsible for the | ||||
| c accuracy of the results. Any publication which utilizes results | ||||
| c from this software should reference the paper listed above. | ||||
| c********************************************************************** | ||||
| c | ||||
| c This version of the program uses the code written for the | ||||
| c Space Forecast Center. The SFC code is modeled after the original | ||||
| c PACE magnetic coordinates code. | ||||
| c | ||||
| c Differences between the original PACE code and the SFC code: | ||||
| c The PACE code was based on Corrected Geomagnetic Coordinates | ||||
| c for 1980, with the conjugate mapping to the southern hemisphere | ||||
| c based on the 1985 IGRF, with time derivatives to model the | ||||
| c field at 1988. | ||||
| c | ||||
| c The PACE code used a spherical expansion of order 4 or less. | ||||
| c The new code ignores the "order" parameter in the call to | ||||
| c cnvcoord, since the SFC code uses an order of 10 and that is | ||||
| c hardcoded. | ||||
| c | ||||
| c The error codes now include -32 to indicate that the | ||||
| c conversion was unsuccessful because the mapping could | ||||
| c not be made to the unit sphere. This condition is also | ||||
| c indicated by the fact that "out_r" has the value 0.0. | ||||
| c | ||||
| c The PACE code calculated a value of "out_r". For a successful | ||||
| c conversion, the value had to be close to 1.0. The SFC code | ||||
| c does not return the value out_r. Therefore, if the conversion | ||||
| c was successful, the value of out_r is set to 1.0 exactly. If | ||||
| c the conversion was not successful, the value of out_r is set | ||||
| c to 0. | ||||
| c | ||||
| c The PACE code returned non-zero values for out_lat and out_long | ||||
| c even if the conversion was not successful (i.e. out_r was not 1.0). | ||||
| c The SFC code will return 0.0, 0.0 if the conversion is not | ||||
| c successful. | ||||
| c | ||||
| c ERROR CODES: | ||||
| c 0 OK | ||||
| c -2 height is invalid (must be between 0 and 2000) | ||||
| c -4 mgflag is invalid (must be 1 or 2) | ||||
| c -8 in_lat is invalid (must be -90.0 to +90.0) | ||||
| c -16 in_long is invalid (must be between -360 and + 360) | ||||
| c -32 conversion was invalid (see above) | ||||
| c | ||||
| cccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc | ||||
| c | ||||
| c Log: cnvcoord.f,v | ||||
| c Revision 3.2 1996/03/20 22:52:00 baker | ||||
| c explicitly declared the size of the integer arguments | ||||
| c to the subroutine. This will help avoid trouble when | ||||
| c mixing C and Fortran on different machines and different | ||||
| c compilers. | ||||
| c | ||||
| c Revision 3.1 1994/10/14 10:39:49 baker | ||||
| c This is the initial version of the wrapper for sfc$$convert_geo_coord. | ||||
| c This version also uses the RCS standards to maintain information about the | ||||
| c revisions. The previous version of cnvcoord was 2.02. That version | ||||
| c is not maintained by RCS. | ||||
| C | ||||
| C Imported by Bill Rideout on April 21, 2010 | ||||
| C Modified by nag_apt to convert all reals to double, int16 to ints | ||||
| C | ||||
| C $Id: cnvcoord.f 3304 2011-01-17 15:25:59Z brideout $ | ||||
| c | ||||
| c | ||||
| DOUBLE PRECISION IN_LAT,IN_LONG,HEIGHT,OUT_LAT,OUT_LONG,OUT_R | ||||
| INTEGER*4 MGFLAG,ERR,ORDER | ||||
| INTEGER*4 I_FLAG,I_ERROR | ||||
| c | ||||
| c | ||||
| c The PACE software accepts in_long values either in the range -180 to | ||||
| c +180 or in the range 0 to 360. The SFC software only allows the | ||||
| c 0 to 360 range. | ||||
| c | ||||
| I_FLAG = MGFLAG | ||||
| IF (IN_LONG.LT.0.0D0) IN_LONG = IN_LONG + 360.0D0 | ||||
| CALL CONVERT_GEO_COORD(IN_LAT,IN_LONG,HEIGHT,OUT_LAT, | ||||
| + OUT_LONG,I_FLAG,I_ERROR) | ||||
| ERR = I_ERROR | ||||
| IF (ERR.EQ.0) THEN | ||||
| OUT_R = 1.0D0 | ||||
| c | ||||
| c The SFC code returns longitudes in the range 0 - 360. The | ||||
| c PACE code has to return the values in the range -180 to +180. | ||||
| c | ||||
| IF (OUT_LONG.GT.180.0D0) OUT_LONG = OUT_LONG - 360.0D0 | ||||
| RETURN | ||||
| ELSE IF (ERR.EQ.-32) THEN | ||||
| OUT_R = 0.0D0 | ||||
| RETURN | ||||
| ELSE | ||||
| RETURN | ||||
| END IF | ||||
| END | ||||
