void latrec_c ( SpiceDouble radius,
SpiceDouble longitude,
SpiceDouble latitude,
SpiceDouble rectan[3] )
Convert from latitudinal coordinates to rectangular coordinates.
None.
CONVERSION, COORDINATES
VARIABLE I/O DESCRIPTION
-------- --- --------------------------------------------------
radius I Distance of a point from the origin.
longitude I Longitude of point in radians.
latitude I Latitude of point in radians.
rectan O Rectangular coordinates of the point.
radius Distance of a point from the origin.
longitude Longitude of the input point. This is the angle between
the prime meridian and the meridian containing `rectan'.
The direction of increasing longitude is from the +X axis
towards the +Y axis.
Longitude is measured in radians. On input, the range
of longitude is unrestricted.
latitude Latitude of the input point. This is the angle from
the XY plane of the ray from the origin through the
point.
Latitude is measured in radians. On input, the range of
latitude is unrestricted.
rectan The rectangular coordinates of the input point.
`rectan' is a 3 vector.
The units associated with `rectan' are those
associated with the input radius.
None.
Error free.
None.
This routine returns the rectangular coordinates of a point
whose position is input in latitudinal coordinates.
Latitudinal coordinates are defined by a distance from a central
reference point, an angle from a reference meridian, and an angle
above the equator of a sphere centered at the central reference
point.
Below are two tables.
Listed in the first table (under r, longitude and latitude ) are
latitudinal coordinate triples that approximately represent
points whose rectangular coordinates are taken from the set
{-1, 0, 1}. (Angular quantities are given in degrees.)
The results of the code fragment
/.
Use the CSPICE routine rpd_c() to convert the angular
quantities to radians
./
latitude *= rpd_c();
longitude *= rpd_c();
latrec_c ( r, longitude, latitude, rectan );
are listed in the second parallel table under rectan[0], rectan[1],
and rectan[2].
r longitude latitude rectan[0] rectan[1] rectan[2].
---------------------------- -------------------------------
0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
1.0000 0.0000 0.0000 1.0000 0.0000 0.0000
1.0000 90.0000 0.0000 0.0000 1.0000 0.0000
1.0000 0.0000 90.0000 0.0000 0.0000 1.0000
1.0000 180.0000 0.0000 -1.0000 0.0000 0.0000
1.0000 -90.0000 0.0000 0.0000 -1.0000 0.0000
1.0000 0.0000 -90.0000 0.0000 0.0000 -1.0000
1.4142 45.0000 0.0000 1.0000 1.0000 0.0000
1.4142 0.0000 45.0000 1.0000 0.0000 1.0000
1.4142 90.0000 45.0000 0.0000 1.0000 1.0000
1.7320 45.0000 35.2643 1.0000 1.0000 1.0000
None.
None.
C.H. Acton (JPL)
N.J. Bachman (JPL)
E.D. Wright (JPL)
W.L. Taber (JPL)
-CSPICE Version 1.0.1, 29-JUL-2003 (NJB) (CHA)
Various header corrections were made.
-CSPICE Version 1.0.0, 16-APR-1999 (EDW)
latitudinal to rectangular coordinates
Link to routine latrec_c source file latrec_c.c
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