- Abstract
Convert from rectangular coordinates to spherical coordinates.
- Required_Reading
None.
- Brief_I/O
VARIABLE I/O DESCRIPTION
-------- --- --------------------------------------------------
rectan I Rectangular coordinates of a point.
r O Distance of the point from the origin.
colat O Angle of the point from the positive Z-axis.
lon O Longitude of the point in radians.
- Detailed_Input
rectan The rectangular coordinates of a point.
- Detailed_Output
r Distance of the point from the origin.
colat Angle between the point and the positive z-axis.
lon Longitude of the point in radians. This is the angle
between the positive X-axis and the orthogonal
projection of the point onto the XY plane. LONG
increases in the counterclockwise sense about the
positive Z-axis. The range of LONG is:
-pi < LONG <= pi
- Parameters
None.
- Particulars
This routine returns the spherical coordinates of a point
whose position is input in rectangular coordinates.
spherical coordinates are defined by a distance from a central
reference point, an angle from a reference meridian, and an angle
from the z-axis.
- Examples
Below are two tables.
Listed in the first table (under X(1), X(2) and X(3) ) are a
number of points whose rectangular coordinates are
taken from the set {-1, 0, 1}.
The result of the code fragment
recsph_c ( X, r, colat, lon )
Use the CSPICE routine convrt_c to convert the angular
quantities to degrees
convrt_c ( colat, "RADIANS", "DEGREES", colat )
convrt_c ( lon, "RADIANS", "DEGREES", lon )
are listed to 4 decimal places in the second parallel table under
r (radius), colat (co-latitude), and lon (longitude).
X(1) X(2) X(3) r colat lon
-------------------------- ----------------------------
0.0000 0.0000 0.0000 0.0000 0.0000 0.0000
1.0000 0.0000 0.0000 1.0000 90.0000 0.0000
0.0000 1.0000 0.0000 1.0000 90.0000 90.0000
0.0000 0.0000 1.0000 1.0000 0.0000 0.0000
-1.0000 0.0000 0.0000 1.0000 90.0000 180.0000
0.0000 -1.0000 0.0000 1.0000 90.0000 -90.0000
0.0000 0.0000 -1.0000 1.0000 180.0000 0.0000
1.0000 1.0000 0.0000 1.4142 90.0000 45.0000
1.0000 0.0000 1.0000 1.4142 45.0000 0.0000
0.0000 1.0000 1.0000 1.4142 45.0000 90.0000
1.0000 1.0000 1.0000 1.7320 54.7356 45.0000
- Restrictions
None.
- Exceptions
Error free.
- Files
None.
- Author_and_Institution
W.L. Taber (JPL)
E.D. Wright (JPL)
- Literature_References
None.
- Version
-CSPICE Version 1.1.1, 07-JAN-2002 (NJB) (EDW)
Fixed description of lon in Brief_I/O and Detailed_I/O
header sections.
-CSPICE Version 1.1.0, 22-OCT-1998 (NJB)
Made input coordinate array const.
-CSPICE Version 1.0.0, 08-FEB-1998 (EDW)
- Index_Entries
rectangular to spherical coordinates
- Link to routine source