spatstat.geom (version 3.7-0)

border: 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, ...)

Value

A window (object of class "owin").

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.

See Also

erosion, dilation

Examples

# rectangle
   u <- unit.square()
   border(u, 0.1)
   border(u, 0.1, outside=TRUE)
# polygon
   opa <- spatstat.options(npixel=32)
   plot(letterR)
   plot(border(letterR, 0.1), add=TRUE)
   plot(border(letterR, 0.1, outside=TRUE), add=TRUE)
   spatstat.options(opa)