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Abstract
I/O
Examples
Particulars
Required Reading
Version
Index_Entries

Abstract


   CSPICE_PL2NVP returns a unit normal vector and point that define a 
   specified plane.

   For important details concerning this module's function, please refer to
   the CSPICE routine pl2nvp_c.

I/O


   Given:

      plane   a structure describing a SPICE plane. The structure has
              the fields:

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

   the call:

      cspice_pl2nvp, plane, normal, point

   returns:

      normal   a double precision 3-vector

      point    a double precision 3-vector

               are, respectively, a unit normal vector and point
               that define the geometric plane represented by
               plane.  Let the symbol < a, b > indicate the inner
               product of vectors a and b; then the geometric
               plane is the set of vectors x in three-dimensional
               space that satisfy

                  < x - point, normal >  =  0.

               'point' is always the closest point in the input
               plane to the origin. 'point' is always a
               non-negative scalar multiple of 'normal'.

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.

      ;;
      ;; A trivial example of plane creation and
      ;; decomposition. Create a plane via the definition
      ;; of a plane normal and constant, determine a
      ;; point in the plane.
      ;;
      plane_norm = [ 2.44d, -5.d/3.d, 11.d/9.d ]
      const      = 3.141592654d

      ;;
      ;; Construct the SPICE plane.
      ;;
      cspice_nvc2pl, plane_norm, const, plane

      ;;
      ;; Convert the plane to a normal vector, point
      ;; representation, 'point' lies in the plane.
      ;;
      cspice_pl2nvp, plane, norm_vec, point
      print, point

   IDL outputs:    0.74966576  -0.51206678   0.37551564

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.

Required Reading


   ICY.REQ
   PLANES.REQ

Version


   -Icy Version 1.0.1, 16-AUG-2010, EDW (JPL)

      Expanded and improved I/O and Particulars sections.

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

Index_Entries


   plane to normal vector and point




Wed Apr  5 17:58:02 2017