R help - Jun 2011 - alphahull: is low level plotting possible?

Dear R users,
I am using package alphahull version 0.2-0 with R-2.13.0. Here is my problem.
I have produced a 2-D plot of points and need to draw convex hulls around some
subsets of these points. So I just need to add the convex hulls to the already
existing plot. That is why I cannot use the plot.hull function. So, is there a
way to just add the convex hulls to the already existing plot, just as the low
level functions "lines" and "points" add lines and points to
an already existing plot? I suspect the solution is in the "arc"
function, but I am not sure.

Any suggestions will be appreciated.

Regards,

Martin

Hi
> 
>  Dear R users,
> I am using package alphahull version 0.2-0 with R-2.13.0. Here is my 
problem.
> I have produced a 2-D plot of points and need to draw convex hulls 
around 
> some subsets of these points. So I just need to add the convex hulls to 
> the already existing plot. That is why I cannot use the plot.hull 
> function. So, is there a way to just add the convex hulls to the already 
> existing plot, just as the low level functions "lines" and
"points" add
> lines and points to an already existing plot? I suspect the solution is 
in
> the "arc" function, but I am not sure.
See ?chull and its help page.

Regards
Petr
> 
> Any suggestions will be appreciated.
> 
> Regards,
> 
> Martin
> 
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