https://github.com/cran/spatstat
Tip revision: 66f0f4d8acdd3844b8bbd102eb70f3f898dc883c authored by Adrian Baddeley on 16 May 2010, 16:21:34 UTC
version 1.19-0
version 1.19-0
Tip revision: 66f0f4d
border.Rd
\name{border}
\alias{border}
\title{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{
\item{w}{A window (object of class \code{"owin"})
or something acceptable to \code{\link{as.owin}}.
}
\item{r}{Numerical value.}
\item{outside}{Logical value determining whether to compute the
border outside or inside \code{w}.}
\item{\dots}{
Optional arguments passed to \code{\link{erosion}}
(if \code{outside=FALSE}) or to \code{\link{dilation}}
(if \code{outside=TRUE}).
}
}
\value{
A window (object of class \code{"owin"}).
}
\details{
By default (if \code{outside=FALSE}),
the border region is the subset of \code{w}
lying within a distance \code{r} of the boundary of \code{w}.
It is computed by eroding \code{w} by the distance \code{r} (using
\code{\link{erosion}}) and
subtracting this eroded window from the original window \code{w}.
If \code{outside=TRUE}, the border region is the set of locations
outside \code{w} lying within a distance \code{r} of \code{w}.
It is computed by dilating \code{w} by the distance \code{r}
(using \code{\link{dilation}}) and
subtracting the original window \code{w} from the dilated window.
}
\author{Adrian Baddeley
\email{adrian@maths.uwa.edu.au}
\url{http://www.maths.uwa.edu.au/~adrian/}
and Rolf Turner
\email{r.turner@auckland.ac.nz}
}
\seealso{
\code{\link{erosion}},
\code{\link{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)
}
\keyword{spatial}
\keyword{math}