cspice_pltnp

 Abstract I/O Examples Particulars Required Reading Version Index_Entries

#### Abstract

```
CSPICE_PLTNP finds the nearest point on a triangular plate to a
given point.

```

#### I/O

```
Given:

point      is an arbitrary point in 3-dimensional space.

[3,1] = size(point); double = class(point)

v1,
v2,
v3         are 3-vectors constituting the vertices of
a triangular plate.

The plate is allowed to be degenerate: it may
consist of a line segment or of a single point.

[3,1] = size(v1); double = class(v1)
[3,1] = size(v2); double = class(v2)
[3,1] = size(v3); double = class(v3)

the call:

[pnear, dist] = cspice_pltnp(point, v1, v2, v3)

returns:

pnear      is the closest point on the plate to `point'.
`pnear' is unique, since the plate is convex.

[3,1] = size(pnear); double = class(pnear)

dist       is the distance between `point' and `pnear'.

[1,1] = size(dist); double = class(dist)

```

#### 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.

Example(1):

Find the nearest point to the point (2,2,2) on a plate having
vertices at the unit basis vectors that lie along the positive
X, Y, and Z coordinate axes.

function pltnp_t

point = [2.0, 2.0, 2.0]';
v1    = [1.0, 0.0, 0.0]';
v2    = [0.0, 1.0, 0.0]';
v3    = [0.0, 0.0, 1.0]';

[pnear, dist] = cspice_pltnp(point, v1, v2, v3);

fprintf ( [ '\n' ...
'Plate vertex 1 = %14.7e %14.7e %14.7e\n' ...
'Plate vertex 2 = %14.7e %14.7e %14.7e\n' ...
'Plate vertex 3 = %14.7e %14.7e %14.7e\n' ...
'Input point    = %14.7e %14.7e %14.7e\n' ...
'\n'                                      ...
'Near point     = %14.7e %14.7e %14.7e\n' ...
'Distance       = %14.7e\n'               ...
'\n'],                                    ...
v1(1),    v1(2),    v1(3),                ...
v2(1),    v2(2),    v2(3),                ...
v3(1),    v3(2),    v3(3),                ...
point(1), point(2), point(3),             ...
pnear(1), pnear(2), pnear(3),             ...
dist                                    )

Matlab outputs:

Plate vertex 1 =  1.0000000e+00  0.0000000e+00  0.0000000e+00
Plate vertex 2 =  0.0000000e+00  1.0000000e+00  0.0000000e+00
Plate vertex 3 =  0.0000000e+00  0.0000000e+00  1.0000000e+00
Input point    =  2.0000000e+00  2.0000000e+00  2.0000000e+00

Near point     =  3.3333333e-01  3.3333333e-01  3.3333333e-01
Distance       =  2.8867513e+00

```

#### Particulars

```
None.

```

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

MICE.REQ
DSK.REQ

```

#### Version

```
-Mice Version 1.0.0, 16-MAR-2016, EDW (JPL), NJB (JPL)

```

#### Index_Entries

```
nearest point on triangular plate

```
`Wed Apr  5 18:00:34 2017`