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\name{density.splitppp}
\alias{density.splitppp}
\alias{density.ppplist}
\title{Kernel Smoothed Intensity of Split Point Pattern}
\description{
Compute a kernel smoothed intensity function for each
of the components of a split point pattern,
or each of the point patterns in a list.
}
\usage{
\method{density}{splitppp}(x, \dots, weights=NULL, se=FALSE)
\method{density}{ppplist}(x, \dots, weights=NULL, se=FALSE)
}
\arguments{
\item{x}{
Split point pattern (object of class \code{"splitppp"}
created by \code{\link[spatstat.geom]{split.ppp}}) to be smoothed.
Alternatively a list of point patterns,
of class \code{"ppplist"}.
}
\item{\dots}{
Arguments passed to \code{\link{density.ppp}} to control
the smoothing, pixel resolution, edge correction etc.
}
\item{weights}{
Numerical weights for the points. See Details.
}
\item{se}{
Logical value indicating whether to compute standard errors as well.
}
}
\value{
A list of pixel images (objects of class \code{"im"})
which can be plotted or printed;
or a list of numeric vectors giving the values at specified points.
If \code{se=TRUE}, the result is a list with two elements named
\code{estimate} and \code{SE}, each of the format described above.
}
\details{
This is a method for the generic function \code{density}.
The argument \code{x} should be a list of point patterns,
and should belong to one of the classes
\code{"ppplist"} or \code{"splitppp"}.
Typically \code{x} is obtained by applying
the function \code{\link[spatstat.geom]{split.ppp}} to a point pattern \code{y}
by calling \code{split(y)}. This splits the points of \code{y} into several
sub-patterns.
A kernel estimate of the intensity function of each of the
point patterns is computed using \code{\link{density.ppp}}.
The return value is usually a list, each of whose entries is a
pixel image (object of class \code{"im"}). The return value
also belongs to the class \code{"solist"} and can be plotted
or printed.
If the argument \code{at="points"} is given, the result is a list
of numeric vectors giving the intensity values at the data points.
If \code{se=TRUE}, the result is a list with two elements named
\code{estimate} and \code{SE}, each of the format described above.
The argument \code{weights} specifies numerical case weights
for the data points.
Normally it should be a list, with the same length as
\code{x}. The entry \code{weights[[i]]} will determine the
case weights for the pattern \code{x[[i]]}, and may be given in
any format acceptable to \code{\link{density.ppp}}.
For example, \code{weights[[i]]} can be
a numeric vector of length equal to \code{npoints(x[[i]])},
a single numeric value, a numeric matrix,
a pixel image (object of class \code{"im"}),
an \code{expression}, or a function of class \code{"funxy"}.
For convenience, \code{weights} can also be a single \code{expression},
or a single pixel image (object of class \code{"im"}),
or a single function of class \code{"funxy"}.
}
\seealso{
\code{\link[spatstat.geom]{ppp.object}},
\code{\link[spatstat.geom]{im.object}}
}
\examples{
Z <- density(split(amacrine), 0.05)
plot(Z)
}
\author{
\spatstatAuthors.
}
\keyword{spatial}
\keyword{methods}
\keyword{smooth}
|
