[R] in par(mfrow=c(1, 2)), how to keep one half plot static and the other half changing

[Duncan Murdoch]

On 12-11-27 10:46 AM, Baoqiang Cao wrote:
> Hi,
>
> I'm trying to plot something in the following way and would like if
> you could help:
>
> I'd like in a same plot window, two plots are shown, the left one is a
> bird-view plot of the whole data, the right half keep changing, i.e.,
> different plots will be shown up on request, so that when I
> select/click on some where in the left plot, the right plot will be
> the corresponding plot.
>
> What I did is:
>
> par(mfrow=c(1,2))
> plot(x, y)
>
> while(1) {
> ...
> pxy <- locator(1, type="p")
>
> #select data point (dx,dy) based on pxy for a new plot
> ..
>
> plot(dx,dy)
> }
>
> I ended up with the left plot is overwritten by plot(dx,dy). Is there
> anyway to keep the left side intact while changing plots on the right
> side?
>

Yes, use the "mfg" option of par().  For example,

par(mfrow=c(1,2))
plot(1)
for (i in 1:100) {
   par(mfg=c(1,2))
   plot(i)
}

Since this overplots each time, you may need something fancy to clear 
the display (e.g. see ?rect).

Duncan