[R] conditioning variable in panel.xyplot?

[Deepayan Sarkar]

On Thu, Mar 4, 2010 at 4:42 PM, Seth W Bigelow <sbigelow at fs.fed.us> wrote:
> I wish to create a multipanel plot (map) from several datasets ("d" and
> "q" in the example below). I can condition the main xyplot statement on
> the "site" variable, but I don't know how to pass a conditioning variable
> to panel.xyplot plot so that the x-y coordinates from dataset q are only
> plotted at the appropriate site.

The keyword is 'subscripts'. Look at the entry for 'panel' in ?xyplot,
and let us know if you still have doubts.

-Deepayan

>
>
> library(lattice)
> d <- data.frame(site  = c(rep("A",12), rep("B",12)),
> x=rnorm(24),y=rnorm(24))                        # Create dataframe "d",
> with 12 x-y coordinates for each site
> q <- data.frame(site  = c(rep("A",7), rep("B",7)),
> x=rnorm(14),y=rnorm(14))                        # Create dataframe "q",
> with 7 pairs of x-y coordinates for each site.
>
> mypanel <- function(...){
>        panel.xyplot(q$x, q$y, col="red")               # Statement that
> needs a "Site" conditioning variable
>        panel.xyplot(...)}
>
> xyplot(y~x|site, d, panel=mypanel)      # Statement erroneously plots all
> 14 x-y points in "q" on panels for sites A & B
>
>
>
> Dr. Seth  W. Bigelow
> Biologist, USDA-FS Pacific Southwest Research Station
> 1731 Research Park Drive, Davis California
>        [[alternative HTML version deleted]]
>
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