\name{is.ppp}
\alias{is.ppp}
\title{Test Whether An Object Is A Point Pattern}
\description{
  Checks whether its argument is a point pattern
  (object of class \code{"ppp"}).
}
\usage{
is.ppp(x)
}
\arguments{
  \item{x}{Any object.}
}
\details{
  This function tests whether the object \code{x}
  is a point pattern object of class
  \code{"ppp"}. See \code{\link{ppm.object}} for details
  of this class.

  The result is determined to be \code{TRUE} if \code{x}
  inherits from \code{"ppp"}, i.e. if \code{x}
  has \code{"ppp"} amongst its classes.
}
\value{
  \code{TRUE} if \code{x} is a point pattern,
  otherwise \code{FALSE}.
}

\author{Adrian Baddeley
  \email{adrian@maths.uwa.edu.au}
  \url{http://www.maths.uwa.edu.au/~adrian/}
  and Rolf Turner
  \email{rolf@math.unb.ca}
  \url{http://www.math.unb.ca/~rolf}
}
\keyword{spatial}