
Computes the border region of a window, that is, the region lying within a specified distance of the boundary of a window.
border(w, r, outside=FALSE, ...)
A window (object of class "owin"
)
or something acceptable to as.owin
.
Numerical value.
Logical value determining whether to compute the
border outside or inside w
.
A window (object of class "owin"
).
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.
# NOT RUN {
# rectangle
u <- unit.square()
border(u, 0.1)
border(u, 0.1, outside=TRUE)
# polygon
# }
# NOT RUN {
data(letterR)
plot(letterR)
plot(border(letterR, 0.1), add=TRUE)
plot(border(letterR, 0.1, outside=TRUE), add=TRUE)
# }
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