https://github.com/cran/RandomFields
Tip revision: 0e562f038613e9388e8c33a6cf59f7f57ae62bf5 authored by Martin Schlather on 03 August 2014, 00:00:00 UTC
version 3.0.32
version 3.0.32
Tip revision: 0e562f0
RMspheric.Rd
\name{RMspheric}
\alias{RMspheric}
\title{Spherical Covariance Model}
\description{
\command{\link{RMspheric}} is a stationary isotropic covariance model
which is only valid up to dimension 3.
The corresponding covariance function only depends on the distance
\eqn{r \ge 0}{r \ge 0} between two points and is given by
\deqn{C(r) = \left(1 - \frac{3}{2} r + \frac{1}{2} r^3\right)
1_{[0,1]}(r)}{C(r) = (1 - 1.5 r + 0.5 r^3) 1_{[0,1]}(r).}
}
\usage{
RMspheric(var, scale, Aniso, proj)
}
\arguments{
\item{var,scale,Aniso,proj}{optional arguments; same meaning for any
\command{\link{RMmodel}}. If not passed, the above
covariance function remains unmodified.}
}
\details{
This covariance model is valid only for dimensions less than or equal
to 3.
The covariance function has a finite range.
}
\value{
\command{\link{RMspheric}} returns an object of class \code{\link[=RMmodel-class]{RMmodel}}
}
\references{
Gelfand, A. E., Diggle, P., Fuentes, M. and Guttorp,
P. (eds.) (2010) \emph{Handbook of Spatial Statistics.}
Boca Raton: Chapman & Hall/CRL.
}
\author{Martin Schlather, \email{schlather@math.uni-mannheim.de}
}
\seealso{
\command{\link{RMmodel}},
\command{\link{RFsimulate}},
\command{\link{RFfit}}.
}
\keyword{spatial}
\keyword{models}
\examples{
RFoptions(seed=0) ## *ANY* simulation will have the random seed 0; set
## RFoptions(seed=NA) to make them all random again
model <- RMspheric()
x <- seq(0, 10, if (interactive()) 0.02 else 1)
plot(model, ylim=c(0,1))
plot(RFsimulate(model, x=x))
\dontshow{FinalizeExample()}
}