Revision 6ebd6ff5fb7707ef87961f50ee794d8eb7143d0a authored by Adrian Baddeley on 10 August 2005, 00:00:00 UTC, committed by Gabor Csardi on 10 August 2005, 00:00:00 UTC
1 parent 5493ce5
cut.ppp.Rd
\name{cut.ppp}
\alias{cut.ppp}
\alias{cut}
\title{Convert Point Pattern Marks from Numeric to Factor}
\description{
Transform the marks of a marked point pattern
from numeric values into a factor.
}
\synopsis{
cut.ppp(x, \dots)
}
\usage{
cut(x, \dots)
cut.ppp(x, \dots)
}
\arguments{
\item{x}{
A two-dimensional point pattern.
An object of class \code{"ppp"}.
This should be a marked point pattern, and the marks would normally
be numerical values.
}
\item{\dots}{
Arguments passed to the generic \code{\link{cut}} function.
They determine the breakpoints for the mapping from numerical values to
factor values. See \code{\link{cut}}.
}
}
\value{
A multitype point pattern, that is, a point pattern object
(of class \code{"ppp"}) with a \code{marks} vector that is a factor.
}
\details{
This simple function applies the generic \code{\link{cut}} operation
to the marks of the point pattern \code{x}. The range of values
of the numerical marks is divided into several intervals, and each
interval is associated with a level of a factor.
The result is a
marked point pattern, with the same window and point locations as
\code{x}, but with the numeric mark of each point discretised
by replacing it by the factor level.
This function is a convenient
way to transform a marked point pattern which has numeric marks
into a multitype point pattern,
for example to plot it or analyse it. See the examples.
To select some points from a point pattern, use the subset operator
\code{\link{[.ppp}} instead.
}
\seealso{
\code{\link{cut}},
\code{\link{ppp.object}}
}
\examples{
data(longleaf)
# Longleaf Pines data
# the marks are positive real numbers indicating tree diameters.
\testonly{
# smaller dataset
longleaf <- longleaf[seq(1, longleaf$n, by=80)]
}
\dontrun{
plot(longleaf)
}
# cut the range of tree diameters into three intervals
long3 <- cut(longleaf, 3)
\dontrun{
plot(long3)
}
# adult trees defined to have diameter at least 30 cm
long2 <- cut(longleaf, breaks=c(0,30,100), labels=c("Sapling", "Adult"))
plot(long2)
plot(long2, cols=c("green","blue"))
}
\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}
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