[R] Overlaying trellis xyplot on contourplot

[Deepayan Sarkar]

On 12/13/07, Seth W Bigelow <sbigelow at fs.fed.us> wrote:
>
> Friends: I wish to overlay data points on a contour graph.  The following
> example produces a nice contour plot, but I have not mastered the concept
> of using panel functions to modify plots. Can someone show me how to
> overlay the data points (given after contour plot statement) on the
> contourplot?

MASS has an example (Figure 4.3); see

file.show(system.file("scripts/ch04.R", package = "MASS"))

-Deepayan