| reccyl_c |
|
Table of contents
Procedure
reccyl_c ( Rectangular to cylindrical coordinates )
void reccyl_c ( ConstSpiceDouble rectan[3],
SpiceDouble * r,
SpiceDouble * clon,
SpiceDouble * z )
AbstractConvert from rectangular to cylindrical coordinates. Required_ReadingNone. KeywordsCONVERSION COORDINATES Brief_I/OVARIABLE I/O DESCRIPTION -------- --- ------------------------------------------------- rectan I Rectangular coordinates of a point. r O Distance of the point from Z axis. clon O Angle (radians) of the point from XZ plane z O Height of the point above XY plane. Detailed_Inputrectan are the rectangular coordinates of the point of interest. Detailed_Output
r is the distance of the point of interest from Z axis.
clon is the cylindrical angle (in radians) of the point of
interest from XZ plane. The `clon' range is [0, 2pi].
z is the height of the point above XY plane.
ParametersNone. ExceptionsError free. FilesNone. ParticularsThis routine transforms the coordinates of a point from rectangular to cylindrical coordinates. Examples
The numerical results shown for these examples may differ across
platforms. The results depend on the SPICE kernels used as
input, the compiler and supporting libraries, and the machine
specific arithmetic implementation.
1) Compute the cylindrical coordinates of the position of the Moon
as seen from the Earth, and convert them to rectangular
coordinates.
Use the meta-kernel shown below to load the required SPICE
kernels.
KPL/MK
File name: reccyl_ex1.tm
This meta-kernel is intended to support operation of SPICE
example programs. The kernels shown here should not be
assumed to contain adequate or correct versions of data
required by SPICE-based user applications.
In order for an application to use this meta-kernel, the
kernels referenced here must be present in the user's
current working directory.
The names and contents of the kernels referenced
by this meta-kernel are as follows:
File name Contents
--------- --------
de421.bsp Planetary ephemeris
naif0012.tls Leapseconds
\begindata
KERNELS_TO_LOAD = ( 'de421.bsp',
'naif0012.tls' )
\begintext
End of meta-kernel
Example code begins here.
/.
Program reccyl_ex1
./
#include <stdio.h>
#include "SpiceUsr.h"
int main( )
{
/.
Local variables
./
SpiceDouble clon;
SpiceDouble et;
SpiceDouble lt;
SpiceDouble pos [3];
SpiceDouble rectan [3];
SpiceDouble r;
SpiceDouble z;
/.
Load SPK and LSK kernels, use a meta kernel for
convenience.
./
furnsh_c ( "reccyl_ex1.tm" );
/.
Look up the geometric state of the Moon as seen from
the Earth at 2017 Mar 20, relative to the J2000
reference frame.
./
str2et_c ( "2017 Mar 20", &et );
spkpos_c ( "Moon", et, "J2000", "NONE", "Earth", pos, < );
/.
Convert the position vector `pos' to cylindrical
coordinates.
./
reccyl_c ( pos, &r, &clon, &z );
/.
Convert the cylindrical to rectangular coordinates.
./
cylrec_c ( r, clon, z, rectan );
printf( " \n" );
printf( "Original rectangular coordinates:\n" );
printf( " \n" );
printf( " X (km): %19.8f\n", pos[0] );
printf( " Y (km): %19.8f\n", pos[1] );
printf( " Z (km): %19.8f\n", pos[2] );
printf( " \n" );
printf( "Cylindrical coordinates:\n" );
printf( " \n" );
printf( " Radius (km): %19.8f\n", r );
printf( " Longitude (deg): %19.8f\n", clon*dpr_c ( ) );
printf( " Z (km): %19.8f\n", z );
printf( " \n" );
printf( "Rectangular coordinates from cylrec_c:\n" );
printf( " \n" );
printf( " X (km): %19.8f\n", rectan[0] );
printf( " Y (km): %19.8f\n", rectan[1] );
printf( " Z (km): %19.8f\n", rectan[2] );
printf( " \n" );
return ( 0 );
}
When this program was executed on a Mac/Intel/cc/64-bit
platform, the output was:
Original rectangular coordinates:
X (km): -55658.44323296
Y (km): -379226.32931475
Z (km): -126505.93063865
Cylindrical coordinates:
Radius (km): 383289.01777726
Longitude (deg): 261.65040211
Z (km): -126505.93063865
Rectangular coordinates from cylrec_c:
X (km): -55658.44323296
Y (km): -379226.32931475
Z (km): -126505.93063865
2) Create a table showing a variety of rectangular coordinates
and the corresponding cylindrical coordinates.
Corresponding rectangular and cylindrical coordinates are
listed to three decimal places. Output angles are in degrees.
Example code begins here.
/.
Program reccyl_ex2
./
#include <stdio.h>
#include "SpiceUsr.h"
int main( )
{
/.
Local parameters.
./
#define NREC 11
/.
Local variables.
./
SpiceDouble clon;
SpiceDouble r;
SpiceDouble z;
SpiceInt i;
/.
Define the input rectangular coordinates.
./
SpiceDouble rectan [NREC][3] = {
{ 0.0, 0.0, 0.0},
{ 1.0, 0.0, 0.0},
{ 0.0, 1.0, 0.0},
{ 0.0, 0.0, 1.0},
{-1.0, 0.0, 0.0},
{ 0.0, -1.0, 0.0},
{ 0.0, 0.0, -1.0},
{ 1.0, 1.0, 0.0},
{ 1.0, 0.0, 1.0},
{ 0.0, 1.0, 1.0},
{ 1.0, 1.0, 1.0} };
/.
Print the banner.
./
printf( " rect[0] rect[1] rect[2] r clon z\n" );
printf( " ------- ------- ------- ------- ------- -------\n" );
/.
Do the conversion. Output angles in degrees.
./
for ( i = 0; i < NREC; i++ )
{
reccyl_c ( rectan[i], &r, &clon, &z );
printf( "%8.3f %8.3f %8.3f ", rectan[i][0], rectan[i][1],
rectan[i][2] );
printf( "%8.3f %8.3f %8.3f\n", r, clon * dpr_c ( ), z );
}
return ( 0 );
}
When this program was executed on a Mac/Intel/cc/64-bit
platform, the output was:
rect[0] rect[1] rect[2] r clon z
------- ------- ------- ------- ------- -------
0.000 0.000 0.000 0.000 0.000 0.000
1.000 0.000 0.000 1.000 0.000 0.000
0.000 1.000 0.000 1.000 90.000 0.000
0.000 0.000 1.000 0.000 0.000 1.000
-1.000 0.000 0.000 1.000 180.000 0.000
0.000 -1.000 0.000 1.000 270.000 0.000
0.000 0.000 -1.000 0.000 0.000 -1.000
1.000 1.000 0.000 1.414 45.000 0.000
1.000 0.000 1.000 1.000 0.000 1.000
0.000 1.000 1.000 1.000 90.000 1.000
1.000 1.000 1.000 1.414 45.000 1.000
RestrictionsNone. Literature_ReferencesNone. Author_and_InstitutionN.J. Bachman (JPL) J. Diaz del Rio (ODC Space) B.V. Semenov (JPL) W.L. Taber (JPL) E.D. Wright (JPL) Version
-CSPICE Version 1.3.0, 04-JUL-2021 (JDR)
Changed the output argument name "lon" to "clon" for consistency
with other routines.
Edited the header to comply with NAIF standard.
Added complete code examples.
-CSPICE Version 1.2.1, 26-JUL-2016 (BVS)
Minor headers edits.
-CSPICE Version 1.2.0, 28-AUG-2001 (NJB)
Removed tab characters from source file. Include interface
macro definition header SpiceZim.h.
-CSPICE Version 1.1.0, 21-OCT-1998 (NJB)
Made input vector const.
-CSPICE Version 1.0.0, 08-FEB-1998 (EDW) (WLT)
Index_Entriesrectangular to cylindrical coordinates |
Fri Dec 31 18:41:11 2021