https://github.com/cran/spatstat
Tip revision: 1a4b153dab7a7656ab810d53e156a13a67e4eea5 authored by Adrian Baddeley on 01 August 2018, 14:50:03 UTC
version 1.56-1
version 1.56-1
Tip revision: 1a4b153
rjitter.Rd
\name{rjitter}
\alias{rjitter}
\title{Random Perturbation of a Point Pattern}
\description{
Applies independent random displacements to each point in a point pattern.
}
\usage{
rjitter(X, radius, retry=TRUE, giveup = 10000, \dots, nsim=1, drop=TRUE)
}
\arguments{
\item{X}{
A point pattern (object of class \code{"ppp"}).
}
\item{radius}{
Scale of perturbations. A positive numerical value.
The displacement vectors will be uniformly
distributed in a circle of this radius.
There is a sensible default.
}
\item{retry}{
What to do when a perturbed point lies outside the window
of the original point pattern. If \code{retry=FALSE},
the point will be lost; if \code{retry=TRUE},
the algorithm will try again.
}
\item{giveup}{
Maximum number of unsuccessful attempts.
}
\item{\dots}{Ignored.}
\item{nsim}{Number of simulated realisations to be generated.}
\item{drop}{
Logical. If \code{nsim=1} and \code{drop=TRUE} (the default), the
result will be a point pattern, rather than a list
containing a point pattern.
}
}
\value{
A point pattern (an object of class \code{"ppp"})
if \code{nsim=1}, or a list of point patterns if \code{nsim > 1},
in the same window as \code{X}.
}
\details{
Each of the points in the point pattern \code{X} is subjected to
an independent random displacement. The displacement vectors are
uniformly distributed in a circle of radius \code{radius}.
If a displaced point lies outside the window, then if
\code{retry=FALSE} the point will be lost.
However if \code{retry=TRUE}, the algorithm will try again: each time a
perturbed point lies outside the window, the algorithm will reject it and
generate another proposed perturbation of the original point,
until one lies inside the window, or until \code{giveup} unsuccessful
attempts have been made. In the latter case, any unresolved points
will be included without any perturbation. The return value will
always be a point pattern with the same number of points as \code{X}.
}
\examples{
X <- rsyst(owin(), 10, 10)
Y <- rjitter(X, 0.02)
plot(Y)
Z <- rjitter(X)
}
\author{\adrian
and \rolf
}
\keyword{spatial}
\keyword{datagen}