gdv.f
58 lines
| 2.0 KiB
| text/x-fortran
|
FortranFixedLexer
| r0 | C $Id: gdv.f 3304 2011-01-17 15:25:59Z brideout $ | |||
| C | ||||
| SUBROUTINE GDV(GDLAT,GCLAT,FR,FT,FP,FX,FY,FZ) | ||||
| C | ||||
| C jmh - 11/79 ans fortran 66 | ||||
| C | ||||
| C GDV converts a vector field f at geodetic latitude GDLAT and | ||||
| C geocentric latitude GCLAT from a geocentric based representation | ||||
| C to a geodetic based representation. the geocentric components | ||||
| C are FR (radial outward), FT (increasing geocentric colatitude, | ||||
| C e.g. southward) and FP (increasing east longitude). the | ||||
| C geodetic components are FX (northward, parallel to surface of | ||||
| C earth), FY (eastward, parallel to surface of earth) and FZ | ||||
| C (downward, perpendicular to surface of earth). FR,FT,FP thus | ||||
| C correspond to spherical coordinates r,theta,phi, with their | ||||
| C origin at the center of the earth. x,y,z are the coordinates | ||||
| C customarily used to describe the three components of the | ||||
| C geomagnetic field. FP and FY are the same. | ||||
| C | ||||
| C Input: | ||||
| C GDLAT - geodetic latitude (degrees) | ||||
| C GCLAT - geocentric latitude (degrees) | ||||
| C FR - radial outward (geocentric). | ||||
| C FT - increasing geocentric colatitude (southward). | ||||
| C FP - increasing east longitude. | ||||
| C | ||||
| C Output: | ||||
| C FX - northward, parallel to surface of earth (geodetic). | ||||
| C FY - eastward, parallel to surface of earth. | ||||
| C FZ - downward, perpendicular to surface of earth. | ||||
| C | ||||
| C .. Scalar Arguments .. | ||||
| DOUBLE PRECISION FP,FR,FT,FX,FY,FZ,GCLAT,GDLAT | ||||
| C .. | ||||
| C .. Local Scalars .. | ||||
| DOUBLE PRECISION COSD,COSLAT,CT,DTR,GDL,SIND,SINLAT,ST,T | ||||
| C .. | ||||
| C .. Intrinsic Functions .. | ||||
| INTRINSIC DCOS,DSIN | ||||
| C .. | ||||
| C .. Data statements .. | ||||
| DATA DTR/.0174532925199D0/ | ||||
| C .. | ||||
| C | ||||
| GDL = DTR*GDLAT | ||||
| SINLAT = DSIN(GDL) | ||||
| COSLAT = DCOS(GDL) | ||||
| T = DTR*(90.D0-GCLAT) | ||||
| CT = DCOS(T) | ||||
| ST = DSIN(T) | ||||
| SIND = ST*SINLAT - CT*COSLAT | ||||
| COSD = CT*SINLAT + ST*COSLAT | ||||
| FX = -FT*COSD - FR*SIND | ||||
| FY = FP | ||||
| FZ = FT*SIND - FR*COSD | ||||
| RETURN | ||||
| C | ||||
| END | ||||
