`spatial_angle`

calculate spatial angle between locations, taking a
dataframe as input. Spatial angle is considered as the angle between the
focus point, the first location entering a given circle and the last location
inside.

`spatial_angle(x, coord.names = c("x", "y"), radius = NULL)`

## Arguments

- x
data.frame with locations

- coord.names
names of coordinates column in `x`

- radius
for angle calculation. Default is median of step length.

## Value

vector of spatial angle.

## Author

Remi Patin, Simon Benhamou.

## Examples

```
if (FALSE) {
data(simulmode)
spatial_angle(simulmode)
}
```