Add direct labels to ggplot2 geom_area chart

Question

This is a continuation of the question here: Create non-overlapping stacked area plot with ggplot2

I have a ggplot2 area chart created by the following code. I want the labels from names be aligned on the right side of the graph. I think directlabels might work, but am willing to try whatever is most clever.

require(ggplot2)
require(plyr)
require(RColorBrewer)
require(RCurl)
require(directlabels)

link <- getURL("http://dl.dropbox.com/u/25609375/so_data/final.txt")
dat <- read.csv(textConnection(link), sep=' ', header=FALSE, 
         col.names=c('count', 'name', 'episode'))


dat <- ddply(dat, .(episode), transform, percent = count / sum(count))

# needed to make geom_area not freak out because of missing value
dat2 <- rbind(dat, data.frame(count = 0, name = 'lane',
                             episode = '02-tea-leaves', percent = 0))

g <- ggplot(arrange(dat2,name,episode), aes(x=episode,y=percent)) + 
  geom_area(aes(fill=name, group = name), position='stack') + scale_fill_brewer()

g1 <- g + geom_dl(method='last.points', aes(label=name))

I'm brand new to directlabels and not really sure how to get the labels to align to right side of the graph with the same colors as the areas.

Answer 1

You can use simple geom_text to add labels. First, subset you data set to get the final x value:

dd=subset(dat, episode=="06-at-the-codfish-ball")

Then order the data frame by factor level:

dd = dd[with(dd, order(name, levels(dd$name))),]

Then work out the cumulative percent for plotting:

dd$cum = cumsum(dd$percent)

Then just use a standard geom_text call:

g + geom_text(data=dd, aes(x=6, y=cum, label=name))

Oh, and you may want to angle your x-axis labels to avoid over plotting:

g + opts(axis.text.x=theme_text(angle=-25, hjust=0.5, size = 8))

Graph