spruces.Rd
\name{spruces}
\alias{spruces}
\docType{data}
\title{
Spruces Point Pattern
}
\description{
The data give the locations of Norwegian spruce trees
in a natural forest stand in Saxonia, Germany.
Each tree is marked with its diameter at breast height.
}
\format{
An object of class \code{"ppp"}
representing the point pattern of tree locations
in a 56 x 38 metre sampling region. Each tree is marked
with its diameter at breast height. All values are given in metres.
See \code{\link{ppp.object}} for details of the format of a
point pattern object. The marks are numeric.
These data have been analysed by Fiksel (1984, 1988),
Stoyan et al (1987), Penttinen et al (1992) and
Goulard et al (1996).
}
\usage{data(spruces)}
\source{Stoyan et al (1987). Original source unknown.}
\examples{
data(spruces)
plot(spruces)
# To reproduce Goulard et al. Figure 3
plot(spruces, maxsize=5*max(spruces$marks))
plot(unmark(spruces), add=TRUE)
}
\references{
Fiksel, T. (1984)
Estimation of parameterized pair potentials of marked and
nonmarked Gibbsian point processes.
\emph{Elektron. Informationsverarb. u. Kybernet.}
\bold{20}, 270--278.
Fiksel, T. (1988)
Estimation of interaction potentials of Gibbsian point processes.
\emph{Statistics}
\bold{19}, 77-86
Goulard, M., S\"arkk\"a, A. and Grabarnik, P. (1996)
Parameter estimation for marked Gibbs point
processes through the maximum pseudolikelihood method.
\emph{Scandinavian Journal of Statistics}
\bold{23}, 365--379.
Penttinen, A., Stoyan, D. and Henttonen, H. (1992)
Marked point processes in forest statistics.
\emph{Forest Science} \bold{38}, 806--824.
Stoyan, D., Kendall, W.S. and Mecke, J. (1987)
\emph{Stochastic Geometry and its Applications}.
Wiley.
}
\keyword{datasets}
\keyword{spatial}