## skyview.geometry Class Util

```java.lang.Object
skyview.geometry.Util
```

`public final class Utilextends java.lang.Object`

Method Summary
`static double[]` `coord(double[] unit)`
Convert a unit vector to the corresponding coordinates.
`static void` ```coord(double[] unit, double[] coord)```
Convert a unit vector to the corresponding coordinates.
`static double` ```sphdist(double lon1, double lat1, double lon2, double lat2)```
Distance between two points on a unit sphere.
`static double` ```sphdistDeg(double lon1, double lat1, double lon2, double lat2)```
Distance between two points on a unit sphere with angles in degres.
`static double[]` `unit(double[] coord)`
Convert a coordinate pair to unit vectors
`static void` ```unit(double[] coord, double[] unitV)```
Convert a coordinate pair to unit vectors.
`static double[]` ```unit(double ra, double dec)```
Convert a coordinate pair to unit vectors

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Method Detail

### unit

```public static double[] unit(double ra,
double dec)```
Convert a coordinate pair to unit vectors

Parameters:
`ra` - The longitude like coordinate in radians.
`dec` - The latitude like coordinate in radians.
Returns:
A double[3] unit vector corresponding to the coordinates.

### unit

`public static double[] unit(double[] coord)`
Convert a coordinate pair to unit vectors

Parameters:
`coord` - The input coordinates
Returns:
A double[3] unit vector corresponding to the coordinates.

### unit

```public static void unit(double[] coord,
double[] unitV)```
Convert a coordinate pair to unit vectors. The user supplies the array to be filled, assumed to be a vector of length 3. are created in this version.

Parameters:
`coord` - A double[2] vector of coordinates.
`unitV` - A pre-allocated double[3] unit vector. The values of this vector will be changed on output.

### coord

`public static double[] coord(double[] unit)`
Convert a unit vector to the corresponding coordinates.

Parameters:
`unit` - A double[3] unit vector.
Returns:
A double[2] coordinate vector.

### coord

```public static void coord(double[] unit,
double[] coord)```
Convert a unit vector to the corresponding coordinates.

Parameters:
`unit` - A double[3] unit vector.
`coord` - A double[2] vector to hold the output coordinates.

### sphdist

```public static double sphdist(double lon1,
double lat1,
double lon2,
double lat2)```
Distance between two points on a unit sphere.

### sphdistDeg

```public static double sphdistDeg(double lon1,
double lat1,
double lon2,
double lat2)```
Distance between two points on a unit sphere with angles in degres.