Geometries can be ill-defined for several reasons, e.g. circles with a radius
of zero, segments that start and end at the same location, etc. See details
for a list of conditions that are considered degenerate.

## Arguments

- x
A geometry vector

## Details

The following conditions are considered to produce degenerate geometries:

A circle having a radius of zero

An iso-rectangle with zero width or zero height

An iso-cuboid with zero width, zero height, or zero depth

A 2D line with the coefficients being zero

A 3D line that is degenerated to a point

A plane with the coefficients being zero

A ray with the source and the second defining point being equal

A segment with the source and target being equal

A sphere with a radius of zero

A tetrahedron with all vertices being co-planar

A triangle with collinear vertices

## Examples

```
# A line without direction
l <- line(point(0, 5), vec(0, 0))
is_degenerate(l)
#> [1] TRUE
# A circle without radius
circ <- circle(point(3, -1), 0)
is_degenerate(circ)
#> [1] TRUE
```