https://github.com/cran/spatstat
Tip revision: 3cabcc19f5c2170689ebcc8ae0a5f5dea2978dde authored by Adrian Baddeley on 26 April 2013, 07:28:25 UTC
version 1.31-2
version 1.31-2
Tip revision: 3cabcc1
fasp.object.Rd
\name{fasp.object}
\alias{fasp.object}
\title{Function Arrays for Spatial Patterns}
\description{
A class \code{"fasp"} to represent a \dQuote{matrix}
of functions, amenable to plotting as a matrix of plot panels.
}
\details{
An object of this class is a convenient way of storing
(and later plotting, editing, etc)
a set of functions \eqn{f_{i,j}(r)}{f[i,j](r)} of a real argument \eqn{r},
defined for each possible pair \eqn{(i,j)} of indices
\eqn{1 \le i,j \le n}{1 <= i,j <= n}. We may think of this
as a matrix or array of functions \eqn{f_{i,j}}{f[i,j]}.
Function arrays are particularly useful in the
analysis of a multitype point pattern (a point pattern in which
the points are identified as belonging to separate types).
We may want to compute a summary function for the points
of type \eqn{i} only, for each of the possible types \eqn{i}.
This produces a \eqn{1 \times m}{1 * m} array of functions.
Alternatively we may compute a summary function
for each possible pair of types \eqn{(i,j)}.
This produces an \eqn{m \times m}{m * m} array of functions.
For multitype point patterns the command \code{\link{alltypes}}
will compute arrays of summary functions for each possible
type or for each possible pair of types.
The function \code{\link{alltypes}}
returns an object of class \code{"fasp"}.
An object of class \code{"fasp"} is a list containing at least the
following components:
\describe{
\item{fns}{
A list of data frames, each representing one of the functions.
}
\item{which}{
A matrix representing the spatial arrangement of the
functions. If \code{which[i,j] = k}
then the function represented by \code{fns[[k]]} should be plotted
in the panel at position \eqn{(i,j)}. If \code{which[i,j] = NA}
then nothing is plotted in that position.
}
\item{titles}{
A list of character strings, providing suitable plotting titles
for the functions.
}
\item{default.formulae}{
A list of default formulae for plotting each of the functions.
}
\item{title}{
A character string, giving a default title for the array
when it is plotted.
}
}
}
\section{Functions available}{
There are methods for \code{plot}, \code{print} and \code{"["}
for this class.
The plot method displays the entire array of functions.
The method \code{\link{[.fasp}} selects a sub-array using the natural
indices \code{i,j}.
The command \code{\link{eval.fasp}} can be used to apply
a transformation to each function in the array,
and to combine two arrays.
}
\seealso{
\code{\link{alltypes}},
\code{\link{plot.fasp}},
\code{\link{[.fasp}},
\code{\link{eval.fasp}}
}
\examples{
# multitype point pattern
data(amacrine)
GG <- alltypes(amacrine, "G")
plot(GG)
# select the row corresponding to cells of type "on"
Gon <- GG["on", ]
plot(Gon)
# extract the G function for i = "on", j = "off"
Gonoff <- GG["on", "off", drop=TRUE]
# Fisher variance stabilising transformation
GGfish <- eval.fasp(asin(sqrt(GG)))
plot(GGfish)
}
\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{attribute}