Trouble with overlapping labels (geom_text) - r

Question

Trouble with overlapping geom_text labels on pie chart
library(scales)
blank_theme <- theme_minimal()+
theme(
axis.title.x = element_blank(),
axis.title.y = element_blank(),
panel.border = element_blank(),
panel.grid=element_blank(),
axis.ticks = element_blank(),
plot.title=element_text(size=14, face="bold")
)
df6 <- data.frame(group = c("Seedling","Ground", "Fern", "Moss"),value = c(2.125,80.125, 11.376,6.375))
# Create a basic bar
pie6 = ggplot(df6, aes(x="", y=value, fill=group)) + geom_bar(stat="identity", width=1) + blank_theme + theme(axis.text.x=element_blank())
# Convert to pie (polar coordinates) and add labels
pie6 = pie6 + coord_polar("y", start=0) + geom_text(aes( label = paste0((value), "%")),position = position_stack(vjust = 0.5))
# Remove labels and add title
pie6 = pie6 + labs(x = NULL, y = NULL, fill = NULL, title = "Understory Composition, Site 2")
# Tidy up the theme
pie6 = pie6 + theme_classic() + theme(axis.line = element_blank(),
axis.text = element_blank(),
axis.ticks = element_blank(),
plot.title = element_text(hjust = 0.5, color = "black"))
pie6
This is my current output. How can i change the labels such that they do not overlap? i have tried various hjust and vjust, positions and position_stack but to no avail
Any help appreciated. thank you.

Answer 1

A manual approach to this problem could be to manipulate the orientation of the text by setting the angle parameter in the geom_text function. This allows you to set the orientation of all text fragments at once by assigning a singel value to angle. You may also set the angle for the individual text items as illustrated below.
ggplot(df6, aes(x = "", y = value, fill = group)) +
geom_bar(stat = "identity", width = 1) +
coord_polar("y", start = 0) +
blank_theme +
theme(axis.text.x = element_blank()) +
geom_text(aes(label = paste0((value), "%")),
position = position_stack(vjust = 0.5),
angle = c(-90, -90, 0, -90)) ####### here
The code below adjust the angle depending on the pie it describes.
ggplot(df6, aes(x = "", y = value, fill = group)) +
geom_bar(stat = "identity", width = 1) +
coord_polar("y", start = 0) +
blank_theme +
theme(axis.text.x = element_blank()) +
geom_text(aes(label = paste0((value), "%")),
position = position_stack(vjust = 0.5),
angle = c(-97, -110, 0, -70)) ####### here
Another way to work around the problem you state, is to play with the start parameter of the coord_polar function:
ggplot(df6, aes(x = "", y = value, fill = group)) +
geom_bar(stat = "identity", width = 1) +
coord_polar("y", start = 180) + ####### here
blank_theme +
theme(axis.text.x = element_blank()) +
geom_text(aes(label = paste0((value), "%")) ,
position = position_stack(vjust = 0.5))

Answer 2

Have you tried using the package ggrepel? If so I recommend. It automatically stops labels overlapping and finds a fit for each other them.
#Install ggrepel package
install.packages("ggrepel", dependencies=TRUE)
df6 <- data.frame(group = c("Seedling","Ground", "Fern", "Moss"),value = c(2.125,80.125, 11.376,6.375))
# Create a basic bar
pie6 = ggplot(df6, aes(x="", y=value, fill=group)) + geom_bar(stat="identity",
width=1) + blank_theme + theme(axis.text.x=element_blank())
# Convert to pie (polar coordinates) and add labels using ggrepel
pie6 = pie6 + coord_polar("y", start=0) + ggrepel::geom_text_repel(aes( label =
paste0((value), "%")),position = position_stack(vjust = 0.5))
# Remove labels and add title
pie6 = pie6 + labs(x = NULL, y = NULL, fill = NULL, title = "Understory Composition, Site 2")
# Tidy up the theme
pie6 = pie6 + theme_classic() + theme(axis.line = element_blank(),
axis.text = element_blank(),
axis.ticks = element_blank(),
plot.title = element_text(hjust = 0.5, color = "black"))
pie6