border

0th

Percentile

Border Region of a Window

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

Keywords
spatial, math
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").

erosion, dilation

• border
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, outside=TRUE), add=TRUE)