cspice_psv2pl

 Abstract I/O Examples Particulars Required Reading Version Index_Entries
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#### Abstract

```
CSPICE_PSV2PL returns a SPICE plane given a point and two spanning vectors.

For important details concerning this module's function, please refer to
the CSPICE routine psv2pl_c.

```

#### I/O

```
Given:

point    a double precision 3-vector

span1    a double precision 3-vector

span2    a double precision 3-vector

are, respectively, a point and two spanning vectors
that define a geometric plane in three-dimensional
space. The plane is the set of vectors

point   +   s * span1   +   t * span2

where 's' and 't' are real numbers. The spanning
vectors 'span1' and 'span2' must be linearly
independent, but they need not be orthogonal or
unitized.

the call:

cspice_psv2pl, point, span1, span2, plane

returns:

plane   a structure representing the SPICE plane as
defined by 'point', 'span1', and 'span2'. The
structure has the fields:

plane.normal:   [3-array double]
plane.constant: [scalar double]

```

#### Examples

```
Any numerical results shown for this example may differ between
platforms as the results depend on the SPICE kernels used as input
and the machine specific arithmetic implementation.

;;
;; Calculate the inclination of the Moon's orbit plane about
;; the Earth to the orbit plane of the Earth around the sun.
;;
;; We want a geometric analysis, so the calculation requires
;; no aberration correction. Use the Ecliptic J2000 frame
;; as a conceptual convenience, however the result is
;; invariant with respect to an inertial frame.
;;
epoch = 'Jan 1 2005'
frame = 'ECLIPJ2000'
corr  = 'NONE'

;;
;; Load the kernels we need to retrieve state data.
;;
cspice_furnsh, 'standard.tm'

;;
;; Convert the time string to  ephemeris time
;;
cspice_str2et, epoch, et

;;
;; Calculate the orbit plane of the Earth about
;; the solar system barycenter at epoch.
;;
cspice_spkezr, 'EARTH', et, frame, corr, \$
'Solar System Barycenter', state, ltime

cspice_psv2pl, state[0:2], state[0:2], state[3:5], es_plane
cspice_pl2nvc, es_plane, es_norm, es_const

;;
;; Calculate the orbit plane of the Moon with respect to
;; the Earth-Moon barycenter at epoch.
;;
cspice_spkezr, 'MOON', et, frame, corr, \$
'EARTH BARYCENTER', state, ltime

cspice_psv2pl, state[0:2], state[0:2], state[3:5], em_plane
cspice_pl2nvc, em_plane, em_norm, em_const

;;
;; Calculate the inclination (output in degrees) from
;; the angle between the plane normals.
;;
;; Depending on the orientation of the plane normals, the
;; cspice_vsep result may exceed 90 degrees. If, so subtract
;; the value off 180 degrees.
;;
loc_inc = cspice_vsep( es_norm, em_norm );

if ( loc_inc GT cspice_halfpi() ) then begin
loc_inc = cspice_pi() - loc_inc
endif

print, 'Moon-Earth orbit plane inclination (degrees): ', \$
loc_inc * cspice_dpr()

IDL outputs:

Moon-Earth orbit plane inclination (degrees):   5.0424957

```

#### Particulars

```
Icy geometry routines that deal with planes use the `plane'
data type to represent input and output planes.  This data type
makes the subroutine interfaces simpler and more uniform.

The Icy routines that produce SPICE planes from data that
define a plane are:

cspice_nvc2pl ( Normal vector and constant to plane )
cspice_nvp2pl ( Normal vector and point to plane    )
cspice_psv2pl ( Point and spanning vectors to plane )

The Icy routines that convert SPICE planes to data that
define a plane are:

cspice_pl2nvc ( Plane to normal vector and constant )
cspice_pl2nvp ( Plane to normal vector and point    )
cspice_pl2psv ( Plane to point and spanning vectors )

Any of these last three routines may be used to convert this
routine's output, 'plane', to another representation of a
geometric plane.

```

```
ICY.REQ
PLANES.REQ

```

#### Version

```
-Icy Version 1.0.1, 01-SEP-2010, EDW (JPL)

Improved the I/O section. The section now meets NAIF standard
for Icy headers. Improved Particulars section.

Corrected example code to perform described function.

-Icy Version 1.0.0, 16-JUN-2003, EDW (JPL)

```

#### Index_Entries

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point and spanning vectors to plane

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`Wed Apr  5 17:58:03 2017`