nestsplit.Rd
\name{nestsplit}
\alias{nestsplit}
\title{
Nested Split
}
\description{
Applies two splitting operations to a point pattern,
producing a list of lists of patterns.
}
\usage{
nestsplit(X, \dots)
}
\arguments{
\item{X}{
Point pattern to be split.
Object of class \code{"ppp"}.
}
\item{\dots}{
Data determining the splitting factors or splitting regions.
See Details.
}
}
\details{
This function splits the point pattern \code{X} into several
sub-patterns using \code{\link{split.ppp}}, then splits each of the
sub-patterns into sub-sub-patterns using \code{\link{split.ppp}}
again.
The result is a hyperframe containing the sub-sub-patterns
and two factors indicating the grouping.
The arguments \code{\dots} determine the two splitting factors
or splitting regions. Each argument may be:
\itemize{
\item a factor (of length equal to the number of points in \code{X})
\item the name of a column of marks of \code{X} (provided this
column contains factor values)
\item a tessellation (class \code{"tess"})
\item a pixel image (class \code{"im"}) with factor values
\item a window (class \code{"owin"})
\item identified by name (in the form \code{name=value})
as one of the formal arguments of \code{\link{quadrats}} or
\code{\link{tess}}
}
The arguments will be processed to yield a list of two
splitting factors/tessellations. The splits will be applied
to \code{X} consecutively to produce the sub-sub-patterns.
}
\value{
A hyperframe with three columns. The first column contains the
sub-sub-patterns. The second and third columns are factors
which identify the grouping according to the two splitting factors.
}
\author{
Original idea by Ute Hahn.
Code by
\adrian
\rolf
and \ege
}
\seealso{
\code{\link{split.ppp}},
\code{\link{quantess}}
}
\examples{
# factor and tessellation
Nft <- nestsplit(amacrine, marks(amacrine), quadrats(amacrine, 3, 1))
Ntf <- nestsplit(amacrine, quadrats(amacrine, 3, 1), marks(amacrine))
Ntf
# two factors
big <- with(marks(betacells), area > 300)
Nff <- nestsplit(betacells, "type", factor(big))
# two tessellations
Tx <- quantess(redwood, "x", 4)
Td <- dirichlet(runifpoint(5, Window(redwood)))
Ntt <- nestsplit(redwood, Td, Tx)
Ntt2 <- nestsplit(redwood, Td, ny=3)
}
\keyword{spatial}
\keyword{manip}