unique.ppp.Rd
\name{unique.ppp}
\alias{unique.ppp}
\title{Extract Unique Points from a Spatial Point Pattern}
\description{
Removes any points that are identical to other points
in a spatial point pattern.
}
\usage{
\method{unique}{ppp}(x, \dots, warn=FALSE)
}
\arguments{
\item{x}{
A spatial point pattern
(object of class \code{"ppp"}).
}
\item{\dots}{
Arguments passed to \code{\link{duplicated.ppp}}.
}
\item{warn}{
Logical. If \code{TRUE}, issue a warning message if any
duplicated points were found.
}
}
\value{
Another point pattern object.
}
\details{
This is a method for the generic function \code{unique} for
point pattern datasets (of class \code{"ppp"}, see \code{\link{ppp.object}}).
Two points in a point pattern are deemed to be identical
if their \eqn{x,y} coordinates are the same,
and their marks are also the same (if they carry marks).
The Examples section illustrates how it is possible for
a point pattern to contain a pair of identical points.
This function removes duplicate points in \code{x},
and returns a point pattern.
}
\seealso{
\code{\link{ppp.object}},
\code{\link{duplicated.ppp}},
\code{\link{multiplicity.ppp}}
}
\examples{
X <- ppp(c(1,1,0.5), c(2,2,1), window=square(3))
unique(X)
unique(X, rule="deldir")
}
\author{Adrian Baddeley
\email{Adrian.Baddeley@csiro.au}
\url{http://www.maths.uwa.edu.au/~adrian/}
and Rolf Turner
\email{r.turner@auckland.ac.nz}
}
\keyword{spatial}
\keyword{methods}