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\name{persp.linim}
\alias{persp.linim}
\title{
Perspective View of Pixel Image on a Linear Network
}
\description{
Given a pixel image on a linear network, generate a perspective view.
}
\usage{
\method{persp}{linim}(x, \dots, main,
grid = TRUE, ngrid = 10,
col.grid = "grey", col.base = "white",
neg.args=list(), warncross=FALSE)
}
\arguments{
\item{x}{
Pixel image on a linear network (object of class \code{"linim"}).
}
\item{\dots}{
Arguments passed to \code{\link[graphics]{persp.default}}
to control the perspective view, or passed to
\code{\link[graphics]{segments}} or \code{\link[graphics]{polygon}}
to control the appearance of the vertical panes.
}
\item{main}{
Main title for the plot.
}
\item{grid}{
Logical value indicating whether to draw a rectangular grid
at height zero, to assist the perception of perspective.
}
\item{ngrid}{
Number of grid lines to draw, if \code{grid=TRUE}.
}
\item{col.grid}{
Colour of grid lines, if \code{grid=TRUE}.
}
\item{col.base}{
Colour of base plane, if \code{grid=TRUE}.
}
\item{neg.args}{
Optional list of arguments passed to \code{\link[graphics]{polygon}}
when displaying negative values of the function.
}
\item{warncross}{
Logical value indicating whether to issue a warning if
two segments of the network cross each other (which causes
difficulty for the algorithm).
}
}
\details{
The pixel values are interpreted as the spatially-varying height of a
vertical surface erected on each segment of the linear network. These
surfaces are drawn in perspective view.
This style of plot is often attributed to Okabe and Sugihara (2012).
}
\value{
(Invisibly) the perspective transformation matrix,
as described in the help for \code{\link[graphics]{persp.default}}.
}
\author{
\adrian and Greg McSwiggan.
}
\seealso{
\code{\link{persp.linfun}}
}
\references{
Okabe, A. and Sugihara, K. (2012)
\emph{Spatial Analysis Along Networks}. John Wiley and Sons, New York.
}
\examples{
if(interactive()) {
Z <- density(chicago, 100)
} else {
X <- runiflpp(10, simplenet)
Z <- density(X, 0.1)
}
persp(Z, theta=30, phi=20)
}
\keyword{spatial}
\keyword{hplot}
\concept{Linear network}
|
