[R] legend in bubble plots made with symbols()

[Denis Chabot]

Hi,

I have read about the use of symbols() to draw circles of different  
sizes, but I have not been able to find out how to add a legend to  
such a graph, legend that would display some specific sizes and their  
meaning.

Before finding the symbols function in Paul Murrell's book, I had  
rolled by own function where the variable I want to use to control  
circle size was actually used to control cex. I was able to draw a  
legend afterward. Symbols seems a bit simpler and I wanted to see if  
it would be better than my own function. But without legend it is  
less useful. However I'm sure there is a way which I'm not aware of  
to draw a legend for a plot drawn with symbols()...

Thanks in advance,

Denis Chabot