\Header{filled.contour}{Level (Contour) Plots}
\keyword{hplot}{filled.contour}
\keyword{aplot}{filled.contour}
\begin{Description}\relax
This function produces a contour plot with the areas between
the contours filled in solid color (Cleveland calls this a
level plot).  A key showing how the colors map to z values
is shown to the right of the plot.\end{Description}
\begin{Usage}
\begin{verbatim}
filled.contour(x = seq(0, 1, len = nrow(z)),
               y = seq(0, 1, len = ncol(z)),
               z,
               xlim = range(x, finite=TRUE),
               ylim = range(y, finite=TRUE),
               zlim = range(z, finite=TRUE),
               levels = pretty(zlim, nlevels), nlevels = 20,
               color.palette = cm.colors,
               col = color.palette(length(levels) - 1),
               plot.title, plot.axes, key.title, key.axes,
               asp = NA, xaxs = "i", yaxs = "i", las = 1, axes = TRUE,
               ...)
\end{verbatim}
\end{Usage}
\begin{Arguments}
\begin{ldescription}
\item[\code{x,y}] locations of grid lines at which the values in \code{z} are
measured.  These must be in ascending order.  By default, equally 
spaced values from 0 to 1 are used.  If \code{x} is a \code{list},
its components \code{x\$x} and \code{x\$y} are used for \code{x}
and \code{y}, respectively. If the list has component \code{z} this
is used for \code{z}.
\item[\code{z}] a matrix containing the values to be plotted (\code{NA}s are
allowed).  Note that \code{x} can be used instead of \code{z} for  
convenience.
\item[\code{xlim}] x limits for the plot.
\item[\code{ylim}] y limits for the plot.
\item[\code{zlim}] z limits for the plot.
\item[\code{levels}] a set of levels which are used to partition the range
of \code{z}.  Areas with \code{z} values between consecutive
levels are painted with the same color.
\item[\code{nlevels}] if \code{levels} is not specified, the range of \code{z},
values is divided into approximately this many levels.
\item[\code{color.palette}] a color palette function to be used to assign
colors in the plot.
\item[\code{col}] an explicit set of colors to be used in the plot.
This argument overrides any palette function specification.
\item[\code{plot.title}] statements which add titles the main plot.
\item[\code{plot.axes}] statements which draw axes on the main plot.
This overrides the default axes.
\item[\code{key.title}] statements which add titles for the plot key.
\item[\code{key.axes}] statements which draw axes on the plot key.
This overrides the default axis.
\item[\code{asp}] the \eqn{y/x}{} aspect ratio, see \code{\Link{plot.window}}.
\item[\code{xaxs}] the x axis style.  The default is to use internal
labeling.
\item[\code{yaxs}] the y axis style.  The default is to use internal
labeling.
\item[\code{las}] the style of labeling to be used.  The default is to
use horizontal labeling. 
\item[\code{...}] additional graphical parameters.
\end{ldescription}
\end{Arguments}
\begin{Note}\relax
This function currently uses the \code{layout} function and so
is restricted to a full page display.  In future it is likely to
be replaced by a genuine \code{levelplot} function which will
work in multipanel displays.\end{Note}
\begin{Author}\relax
Ross Ihaka.\end{Author}
\begin{References}\relax
Cleveland, W. S. (1993)
\emph{Visualizing Data}.
Summit, New Jersey: Hobart.\end{References}
\begin{SeeAlso}\relax
\code{\Link{contour}}, \code{\Link{image}}, \code{\Link{palette}}.\end{SeeAlso}
\begin{Examples}
\begin{ExampleCode}
data(volcano)
filled.contour(volcano, color = terrain.colors, asp = 1)# simple

x <- 10*1:nrow(volcano)
y <- 10*1:ncol(volcano)
filled.contour(x, y, volcano, color = terrain.colors,
    plot.title = title(main = "The Topography of Maunga Whau",
    xlab = "Meters North", ylab = "Meters West"),
    plot.axes = { axis(1, seq(100, 800, by = 100))
                  axis(2, seq(100, 600, by = 100)) },
    key.title = title(main="Height\n(meters)"),
    key.axes = axis(4, seq(90, 190, by = 10)))# maybe also asp=1
mtext(paste("filled.contour(.) from", R.version.string),
      side = 1, line = 4, adj = 1, cex = .66)
\end{ExampleCode}
\end{Examples}

