as.function.tess.Rd
\name{as.function.tess}
\alias{as.function.tess}
\title{
Convert a Tessellation to a Function
}
\description{
Convert a tessellation into a function of the \eqn{x} and \eqn{y} coordinates.
The default function values are factor levels specifying which tile of the
tessellation contains the point \eqn{(x,y)}.
}
\usage{
\method{as.function}{tess}(x,\dots,values=NULL)
}
\arguments{
\item{x}{
A tessellation (object of class \code{"tess"}).
}
\item{values}{
Optional. A vector giving the values of the function for each tile
of \code{x}.
}
\item{\dots}{
Ignored.
}
}
\details{
This command converts a tessellation
(object of class \code{"tess"}) to a \code{function(x,y)}
where the arguments \code{x} and \code{y} are (vectors of) spatial
coordinates. The corresponding function values are factor levels
identifying which tile of the tessellation contains each point.
Values are \code{NA} if the corresponding point lies outside the
tessellation.
If the argument \code{values} is given, then it determines the value
of the function in each tile of \code{x}.
}
\value{
A function in the \R language, also belonging to the
class \code{"funxy"}.
}
\author{
\spatstatAuthors
}
\seealso{
\code{\link{tileindex}} for the low-level calculation of tile index.
\code{\link{cut.ppp}} and \code{\link{split.ppp}} to
divide up the points of a point pattern according to
a tessellation.
}
\examples{
X <- runifpoint(7)
V <- dirichlet(X)
f <- as.function(V)
f(0.1, 0.4)
plot(f)
}
\keyword{spatial}
\keyword{manip}