latrec_c

 Procedure Abstract Required_Reading Keywords Brief_I/O Detailed_Input Detailed_Output Parameters Exceptions Files Particulars Examples Restrictions Literature_References Author_and_Institution Version Index_Entries

#### Procedure

```   void latrec_c ( SpiceDouble    radius,
SpiceDouble    longitude,
SpiceDouble    latitude,
SpiceDouble    rectan )

```

#### Abstract

```   Convert from latitudinal coordinates to rectangular coordinates.
```

```   None.
```

#### Keywords

```   CONVERSION,  COORDINATES

```

#### Brief_I/O

```   VARIABLE  I/O  DESCRIPTION
--------  ---  --------------------------------------------------
radius     I   Distance of a point from the origin.
longitude  I   Longitude of point in radians.
latitude   I   Latitude of point in radians.
rectan     O   Rectangular coordinates of the point.
```

#### Detailed_Input

```   radius     Distance of a point from the origin.

longitude  Longitude of the input point.  This is the angle between
the prime meridian and the meridian containing `rectan'.
The direction of increasing longitude is from the +X axis
towards the +Y axis.

Longitude is measured in radians.  On input, the range
of longitude is unrestricted.

latitude   Latitude of the input point. This is the angle from
the XY plane of the ray from the origin through the
point.

Latitude is measured in radians. On input, the range of
latitude is unrestricted.
```

#### Detailed_Output

```   rectan     The rectangular coordinates of the input point.
`rectan' is a 3 vector.

The units associated with `rectan' are those

#### Parameters

```   None.
```

#### Exceptions

```   Error free.
```

#### Files

```   None.
```

#### Particulars

```   This routine returns the rectangular coordinates of a point
whose position is input in latitudinal coordinates.

Latitudinal coordinates are defined by a distance from a central
reference point, an angle from a reference meridian, and an angle
above the equator of a sphere centered at the central reference
point.
```

#### Examples

```   Below are two tables.

Listed in the first table (under r, longitude and latitude ) are
latitudinal coordinate triples that approximately represent
points whose rectangular coordinates are taken from the set
{-1, 0, 1}.  (Angular quantities are given in degrees.)

The results of the code fragment

/.
Use the CSPICE routine rpd_c() to convert the angular
./
latitude  *= rpd_c();
longitude *= rpd_c();

latrec_c ( r, longitude, latitude, rectan );

are listed in the second parallel table under rectan, rectan,
and rectan.

r       longitude  latitude      rectan  rectan rectan.
----------------------------      -------------------------------
0.0000    0.0000    0.0000         0.0000     0.0000   0.0000
1.0000    0.0000    0.0000         1.0000     0.0000   0.0000
1.0000   90.0000    0.0000         0.0000     1.0000   0.0000
1.0000    0.0000   90.0000         0.0000     0.0000   1.0000
1.0000  180.0000    0.0000        -1.0000     0.0000   0.0000
1.0000  -90.0000    0.0000         0.0000    -1.0000   0.0000
1.0000    0.0000  -90.0000         0.0000     0.0000  -1.0000
1.4142   45.0000    0.0000         1.0000     1.0000   0.0000
1.4142    0.0000   45.0000         1.0000     0.0000   1.0000
1.4142   90.0000   45.0000         0.0000     1.0000   1.0000
1.7320   45.0000   35.2643         1.0000     1.0000   1.0000
```

#### Restrictions

```   None.
```

#### Literature_References

```   None.
```

#### Author_and_Institution

```   C.H. Acton      (JPL)
N.J. Bachman    (JPL)
E.D. Wright     (JPL)
W.L. Taber      (JPL)
```

#### Version

```   -CSPICE Version 1.0.1, 29-JUL-2003 (NJB) (CHA)

```   latitudinal to rectangular coordinates
`Wed Apr  5 17:54:38 2017`