ggplot2 pie and donut chart on same plot

Question

I am trying to replicate this with R ggplot. I have exactly the same data:

browsers<-structure(list(browser = structure(c(3L, 3L, 3L, 3L, 2L, 2L, 
2L, 1L, 5L, 5L, 4L), .Label = c("Chrome", "Firefox", "MSIE", 
"Opera", "Safari"), class = "factor"), version = structure(c(5L, 
6L, 7L, 8L, 2L, 3L, 4L, 1L, 10L, 11L, 9L), .Label = c("Chrome 10.0", 
"Firefox 3.5", "Firefox 3.6", "Firefox 4.0", "MSIE 6.0", "MSIE 7.0", 
"MSIE 8.0", "MSIE 9.0", "Opera 11.x", "Safari 4.0", "Safari 5.0"
), class = "factor"), share = c(10.85, 7.35, 33.06, 2.81, 1.58, 
13.12, 5.43, 9.91, 1.42, 4.55, 1.65), ymax = c(10.85, 18.2, 51.26, 
54.07, 55.65, 68.77, 74.2, 84.11, 85.53, 90.08, 91.73), ymin = c(0, 
10.85, 18.2, 51.26, 54.07, 55.65, 68.77, 74.2, 84.11, 85.53, 
90.08)), .Names = c("browser", "version", "share", "ymax", "ymin"
), row.names = c(NA, -11L), class = "data.frame")

and it looks like this:

> browsers
   browser      version  share   ymax   ymin
1     MSIE     MSIE 6.0  10.85  10.85   0.00
2     MSIE     MSIE 7.0   7.35  18.20  10.85
3     MSIE     MSIE 8.0  33.06  51.26  18.20
4     MSIE     MSIE 9.0   2.81  54.07  51.26
5  Firefox  Firefox 3.5   1.58  55.65  54.07
6  Firefox  Firefox 3.6  13.12  68.77  55.65
7  Firefox  Firefox 4.0   5.43  74.20  68.77
8   Chrome  Chrome 10.0   9.91  84.11  74.20
9   Safari   Safari 4.0   1.42  85.53  84.11
10  Safari   Safari 5.0   4.55  90.08  85.53
11   Opera   Opera 11.x   1.65  91.73  90.08

So far, I have plotted the individual components (i.e. the donut chart of the versions, and the pie chart of the browsers) like so:

ggplot(browsers) + geom_rect(aes(fill=version, ymax=ymax, ymin=ymin, xmax=4, xmin=3)) +
coord_polar(theta="y") + xlim(c(0, 4))

ggplot(browsers) + geom_bar(aes(x = factor(1), fill = browser),width = 1) +
coord_polar(theta="y")

The problem is, how do I combine the two to look like the topmost image? I have tried many ways, such as:

ggplot(browsers) + geom_rect(aes(fill=version, ymax=ymax, ymin=ymin, xmax=4, xmin=3)) +         geom_bar(aes(x = factor(1), fill = browser),width = 1) + coord_polar(theta="y") + xlim(c(0, 4)) 

But all my results are either twisted or end with an error message.

Answer 1

I find it easier to work in rectangular coordinates first, and when that is correct, then switch to polar coordinates. The x coordinate becomes radius in polar. So, in rectangular coordinates, the inside plot goes from zero to a number, like 3, and the outer band goes from 3 to 4.

For example

ggplot(browsers) + 
  geom_rect(aes(fill=version, ymax=ymax, ymin=ymin, xmax=4, xmin=3)) +
  geom_rect(aes(fill=browser, ymax=ymax, ymin=ymin, xmax=3, xmin=0)) +
  xlim(c(0, 4)) + 
  theme(aspect.ratio=1) 

Then, when you switch to polar, you get something like what you are looking for.

ggplot(browsers) + 
  geom_rect(aes(fill=version, ymax=ymax, ymin=ymin, xmax=4, xmin=3)) +
  geom_rect(aes(fill=browser, ymax=ymax, ymin=ymin, xmax=3, xmin=0)) +
  xlim(c(0, 4)) + 
  theme(aspect.ratio=1) +
  coord_polar(theta="y")  

This is a start, but may need to fine tune the dependency on y (or angle) and also work out the labeling / legend / coloring... By using rect for both the inner and outer rings, that should simplify adjusting the coloring. Also, it can be useful to use the reshape2::melt function to reorganize the data so then legend comes out correct by using group (or color).