[R] ggplot: Stacked bar/pie chart - Objects above the bar/pie

[Jim Lemon]

On Fri, 17 Oct 2014 12:52:04 PM Gunnar Oehmichen wrote:
> Hello,
> 
> I would like to draw a circle on top of a pie chart (The plot does not
> need to fullfill scientific standards). The circle represents the
> relation of a reference-value in comparison to the summed values of 
the
> pie-pieces. To be able to do this I partly followed:
> http://rpubs.com/RobinLovelace/11641 . But i have the problem of 
some
> bar/pie pieces being placed above the stacked bar/outside of the pie
> chart, see graph PA / PA + coord_polar.
> 
Hi Gunnar,
I'm not certain that I have got the correct idea of what you want, but 
have a look at this:

library(plotrix)
vals<-by(mdf$value,mdf$variable,sum)
poss<-by(mdf$pos,mdf$variable,sum)
radial.pie(poss,c(0,cumsum(6.28*vals/sum(vals))),
 labels=letters[1:5],show.grid.labels=3,
 radial.lim=c(0,max(poss)))
legend(200000000,200000000,letters[1:5],fill=rainbow(5),
 bg="white")
draw.circle(0,0,radius=poss[2],border="red")

I didn't get exactly where you wanted the circle, so I guessed with the red 
circle.

Jim