Showing variable labels under the segments of dendrogram with ggdendro

Question

My question is related to Andrie's answer to my earlier question. My question is whether is this possible to display the variable labels and car label under the corresponding segments of the dendrogram?

library(ggplot2)
library(ggdendro)
data(mtcars)
x <- as.matrix(scale(mtcars))
dd.row <- as.dendrogram(hclust(dist(t(x))))
ddata_x <- dendro_data(dd.row)
p2 <- ggplot(segment(ddata_x)) +
geom_segment(aes(x=x0, y=y0, xend=x1, yend=y1))
print(p2)

Answer 1

Make sure you have version 0.0-7 of ggdendro and then use the convenience function ggdendrogram:

library(ggplot2)
library(ggdendro)
ggdendrogram(dd.row)

If you want full control over how the labels are displayed, you can extract and manipulate these from ddata_x using either:

ddata_x$labels
label(ddata_x)

To add to your plot:

p2 + geom_text(data=label(ddata_x), aes(label=text, x=x, y=0))

You can find more information in the vignette, vignette("ggdendro")