Tip label angle with radial plotting

[alexskeels]

Attempting to plot tip labels with coord_geo_radial leads to interesting bevahiour. Looks like the labels remain pivoted on the fist letter rather than adjusting for the angle as is done when plotting a circular tree with ggtree.

`library(ape)
library(ggtree)
library(deeptime)
data("chiroptera")

Standard ggtree plot

revts(ggtree(chiroptera, layout="circular") +
geom_tiplab(size=0.8))

Standard ggtree plot with geom_tiplab2 (for circular layout)

revts(ggtree(chiroptera, layout="circular") +
geom_tiplab2(size=0.8))

with coord_geo_radial

revts(ggtree(chiroptera) +
coord_geo_radial( dat = "epochs", abbrv = T)+
geom_tiplab(size=0.8))

with coord_geo_radial - even whackier with geom_tiplab2

revts(ggtree(chiroptera) +
coord_geo_radial( dat = "epochs", abbrv = T)+
geom_tiplab2(size=0.8))`

[willgearty]

OK, after lots of experimenting, I've discovered that this appears to be an assumption within geom_tiplab2() that the start/end of the circular phylogeny is on the right side of the plot. So, in fact, using coord_geo_polar() with geom_tiplab2() works:

library(ggplot2)
library(ggtree)
library(deeptime)
library(ape)
data("chiroptera")
revts(ggtree(chiroptera) +
          coord_geo_polar(theta = "y") +
          geom_tiplab2(size=0.8))

^{Created on 2024-10-24 with reprex v2.1.1}

You could change the y-scale to get a gap like in coord_geo_radial():

library(ggplot2)
library(ggtree)
library(deeptime)
library(ape)
data("chiroptera")
revts(ggtree(chiroptera) +
          coord_geo_polar("epochs") +
          scale_y_continuous(limits = c(0, NA), expand = expansion(0, c(0.6, 20))) +
          geom_tiplab2(size = 0.8))

^{Created on 2024-10-24 with reprex v2.1.1}

But, we can go a step further and use coord_geo_radial() with just some minor tweaks stolen from coord_geo_polar() to make the phylogeny start and end on the right:

library(ggplot2)
library(ggtree)
library(deeptime)
library(ape)
data("chiroptera")
revts(ggtree(chiroptera) +
          coord_geo_radial("epochs", start = -pi/2, direction = -1) +
          geom_tiplab2(size = 0.8))

^{Created on 2024-10-24 with reprex v2.1.1}

Tada!

[willgearty]

I've reached out to the ggtree folks to see if we can get geom_tiplab2() to work with any fan phylogeny orientation.