Revision 2cce766bb3e656de2c829da29ab8c51681004900 authored by Adrian Baddeley on 11 November 2010, 00:00:00 UTC, committed by Gabor Csardi on 11 November 2010, 00:00:00 UTC
1 parent 6bd38f3
marks.Rd
\name{marks}
\alias{marks}
\alias{marks.ppp}
\alias{marks.ppx}
\alias{marks<-}
\alias{marks<-.ppp}
\alias{marks<-.ppx}
\alias{setmarks}
\alias{\%mark\%}
\title{Marks of a Point Pattern}
\description{
Extract or change the marks attached to
a point pattern dataset.
}
\usage{
marks(x, \dots)
\method{marks}{ppp}(x, \dots, dfok=TRUE)
\method{marks}{ppx}(x, \dots, drop=TRUE)
marks(x, \dots) <- value
\method{marks}{ppp}(x, \dots, dfok=TRUE) <- value
\method{marks}{ppx}(x, \dots) <- value
setmarks(x, value)
x \%mark\% value
}
\arguments{
\item{x}{
Point pattern dataset (object of class \code{"ppp"} or \code{"ppx"}).
}
\item{\dots}{
Ignored.
}
\item{dfok}{
Logical. If \code{FALSE}, data frames of marks are not permitted
and will generate an error.
}
\item{drop}{
Logical. If \code{TRUE}, a data frame consisting of a single column
of marks will be converted to a vector or factor.
}
\item{value}{
Vector, data frame or hyperframe of mark values,
or \code{NULL}.
}
}
\value{
For \code{marks(x)}, the result is a vector, factor, data frame or hyperframe,
containing the mark values attached to the points of \code{x}.
For \code{marks(x) <- value}, the result is the updated point pattern
\code{x} (with the side-effect that the dataset \code{x} is updated in
the current environment).
For \code{setmarks(x,value)} and \code{x \%mark\% value}, the return value
is the point pattern obtained by replacing the
marks of \code{x} by \code{value}.
}
\details{
These functions extract or change the marks
attached to the points of the point pattern \code{x}.
The expression \code{marks(x)} extracts the marks of \code{x}.
The assignment \code{marks(x) <- value} assigns new marks to the
dataset \code{x}, and updates the dataset \code{x} in the current
environment. The expression \code{setmarks(x,value)}
or equivalently \code{x \%mark\% value} returns a point pattern
obtained by replacing the marks of \code{x} by \code{value}, but does
not change the dataset \code{x} itself.
For point patterns in two-dimensional space (objects of class
\code{"ppp"}) the marks can be a vector, a factor, or a data frame.
For general point patterns (objects of class "ppx") the
marks can be a vector, a factor, a data frame or a
hyperframe.
For the assignment \code{marks(x) <- value}, the \code{value}
should be a vector or factor of length equal to the number of
points in \code{x}, or a data frame or hyperframe with as many rows
as there are points in \code{x}. If \code{value} is a single value,
or a data frame or hyperframe with one row, then it will be replicated
so that the same marks will be attached to each point.
To remove marks, use \code{marks(x) <- NULL} or
\code{\link{unmark}(x)}.
Use \code{\link{ppp}} or \code{\link{ppx}}
to create point patterns in more general
situations.
}
\seealso{
\code{\link{ppp.object}},
\code{\link{ppx}},
\code{\link{unmark}},
\code{\link{hyperframe}}
}
\examples{
data(amacrine)
# extract marks
m <- marks(amacrine)
# recode the mark values "off", "on" as 0, 1
marks(amacrine) <- as.integer(m == "on")
}
\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{manip}
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