R: Border Region of a Window

border {spatstat} | R Documentation

## Border Region of a Window

### Description

Computes the border region of a window, that is, the region lying within a specified distance of the boundary of a window.

### Usage

    border(w, r, outside=FALSE, ...)

### Arguments

`w` | A window (object of class `"owin"`) or something acceptable to `as.owin`.
`r` | Numerical value.
`outside` | Logical value determining whether to compute the border outside or inside `w`.
`...` | Optional arguments passed to `erosion` (if `outside=FALSE`) or to `dilation` (if `outside=TRUE`).

### Details

By default (if `outside=FALSE`), the border region is the subset of `w` lying within a distance `r` of the boundary of `w`. It is computed by eroding `w` by the distance `r` (using `erosion`) and subtracting this eroded window from the original window `w`.

If `outside=TRUE`, the border region is the set of locations outside `w` lying within a distance `r` of `w`. It is computed by dilating `w` by the distance `r` (using `dilation`) and subtracting the original window `w` from the dilated window.

### Value

A window (object of class `"owin"`).

### Author(s)

Adrian Baddeley Adrian.Baddeley@curtin.edu.au

and Rolf Turner r.turner@auckland.ac.nz

### See Also

`erosion`, `dilation`

### Examples

    # rectangle
       u <- unit.square()
       border(u, 0.1)
       border(u, 0.1, outside=TRUE)
    # polygon

       data(letterR)
       plot(letterR)
       plot(border(letterR, 0.1), add=TRUE)
       plot(border(letterR, 0.1, outside=TRUE), add=TRUE)

[Package spatstat version 1.54-0 Index]