https://github.com/cran/spatstat
Tip revision: cd674f37c3fcb1e480ff95e091708ec4ada60212 authored by Adrian Baddeley on 10 February 2011, 08:22:40 UTC
version 1.21-5
version 1.21-5
Tip revision: cd674f3
cut.im.Rd
\name{cut.im}
\alias{cut.im}
\title{Convert Pixel Image from Numeric to Factor}
\description{
Transform the values of a pixel image
from numeric values into a factor.
}
\usage{
\method{cut}{im}(x, \dots)
}
\arguments{
\item{x}{
A pixel image.
An object of class \code{"im"}.
}
\item{\dots}{
Arguments passed to \code{\link{cut.default}}.
They determine the breakpoints for the mapping from numerical values to
factor values. See \code{\link{cut.default}}.
}
}
\value{
A pixel image (object of class \code{"im"}) with
pixel values that are a factor.
See \code{\link{im.object}}.
}
\details{
This simple function applies the generic \code{\link{cut}} operation
to the pixel values of the image \code{x}. The range of pixel values
is divided into several intervals, and each
interval is associated with a level of a factor.
The result is another pixel image,
with the same window and pixel grid as
\code{x}, but with the numeric value of each pixel discretised
by replacing it by the factor level.
This function is a convenient
way to inspect an image and to obtain summary statistics.
See the examples.
To select a subset of an image, use the subset operator
\code{\link{[.im}} instead.
}
\seealso{
\code{\link{cut}},
\code{\link{im.object}}
}
\examples{
# artificial image data
Z <- setcov(square(1))
Y <- cut(Z, 3)
Y <- cut(Z, breaks=seq(0,1,length=5))
# cut at the quartiles
# (divides the image into 4 equal areas)
Y <- cut(Z, quantile(Z))
}
\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{methods}