add layer to specific panel of facet_plot output

This is a question from ggtree google group:

Dear ggtree team,

how can I apply a geom_xxx to only one facet panel? For example if i want to get geom_hline(yintersect=1:30) or a geom_text() in the dot panel? I cant see the facet_grid(. ~ var) function call, so I don’t know which subsetting to use. I have already read http://stackoverflow.com/questions/29873155/geom-text-and-facets-not-working

  tr <- rtree(30)
  d1 <- data.frame(id=tr$tip.label, val=rnorm(30, sd=3))
  p <- ggtree(tr)
  p2 <- facet_plot(p, panel="dot", data=d1, geom=geom_point, aes(x=val), color='firebrick')
  d2 <- data.frame(id=tr$tip.label, value = abs(rnorm(30, mean=100, sd=50)))
  p3 <- facet_plot(p2, panel='bar', data=d2, geom=geom_segment, aes(x=0, xend=value, y=y, yend=y), size=3, color='steelblue') + theme_tree2()

Thanks! Andreas

If this can be done, we can create even more comprehensive tree plots.

xlim_tree: set x axis limits for only Tree panel

A ggtree user recently asked me the following question in google group:

I try to plot long tip labels in ggtree and usually adjust them using xlim(), however when creating a facet_plot xlim affects all plots and minimizes them.

Is it possible to work around this and only affect the tree and it’s tip labels leaving the other plots in facet_plot unaffected?

This is indeed a desire feature, as ggplot2 can’t automatically adjust xlim for text since the units are in two different spaces (data and pixel).

facet_plot: a general solution to associate data with phylogenetic tree

ggtree provides gheatmap for visualizing heatmap and msaplot for visualizing multiple sequence alignment with phylogenetic tree.

We may have different data types and want to visualize and align them with the tree. For example, dotplot of SNP site (e.g. using geom_point(shape='|')), barplot of trait values (e.g. using geom_barh(stat='identity')) et al.

To make it easy to associate different types of data with phylogenetic tree, I implemented the facet_plot function which accepts a geom function to draw the input data.frame and display it in an additional panel.

an example of drawing beast tree using ggtree

FigTree is designed for viewing beast output as demonstrated by their example data:

viewing and annotating phylogenetic tree with ggtree

When I need to annotate nucleotide substitutions in the phylogenetic tree, I found that all the software are designed to display the tree but not annotating it. Some of them may support annotating the tree with specific data such as bootstrap values, but they are restricted to a few supported data types. It is hard/impossible to inject user specific data.