Select `n`

landmarks that are spaced with a regular sequence of angles taken
between the outline coordinates and the centroid.

## Arguments

- x
A

`matrix`

, a`data.frame`

a`list`

of perimeter coordinates, often produced with`object_contour()`

.- n
Number of points to be sampled. Defaults to 50.

- close
Return a closed polygon? Defaults to

`TRUE`

.- plot
Create a plot? Defaults to

`TRUE`

.- ncol, nrow
The number of rows or columns in the plot grid when a

`list`

is used in`x`

. Defaults to`NULL`

, i.e., a square grid is produced.

## Value

A list with the following objects:

`pixindices`

: Vector of radius indices.`radii`

: Vector of sampled radii lengths.`Xc`

: The centroid coordinate of`x`

axis.`Yc`

: The centroid coordinate of`y`

axis.`coords`

: Coordinates of sampled points arranged in a two-column matrix.

If `x`

is a list, a list of objects described above is returned.

## Examples

```
library(pliman)
plot_polygon(contours[[1]])
ldm <- landmarks_regradi(contours)
```