\name{perimeter}
\Rdversion{1.1}
\alias{perimeter}
\title{
Perimeter Length of Window
}
\description{
Computes the perimeter length of a window
}
\usage{
perimeter(w)
}
\arguments{
\item{w}{
A window (object of class \code{"owin"})
or data that can be converted to a window by \code{\link{as.owin}}.
}
}
\details{
This function computes the perimeter (length of the boundary) of the
window \code{w}. If \code{w} is a rectangle or a polygonal window,
the perimeter is the sum of the lengths of the edges of \code{w}.
If \code{w} is a mask, it is first converted to a polygonal window
using \code{\link{as.polygonal}}, then staircase edges are removed
using \code{\link{simplify.owin}}, and the perimeter of the resulting
polygon is computed.
}
\value{
A numeric value giving the perimeter length of the window.
}
\seealso{
\code{\link{area.owin}}
\code{\link{diameter.owin}},
\code{\link{owin.object}},
\code{\link{as.owin}}
}
\examples{
perimeter(square(3))
data(letterR)
perimeter(letterR)
if(spatstat.options("gpclib")) {
if(interactive()) {
print(perimeter(as.mask(letterR)))
} else print(perimeter(as.mask(letterR, dimyx=32)))
}
}
\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}
}
\keyword{spatial}
\keyword{math}