Are there any examples to avoid label overlap in pie chart?

[shenweiyan]

I have a problem with labeling percent in pie charts. Some labels are overlapped since the space is not enough to distinctively show them.

[slowkow]

Annotate pie charts with ggrepel

Kamil Slowikowski
2020-03-18

Let’s make some data:

library(ggplot2)
df <- data.frame(
  group = c("Antelope", "Bird", "Cat", "Dog", "Eel"),
  value = c(25, 25, 50, 1, 1)
)
df

##      group value
## 1 Antelope    25
## 2     Bird    25
## 3      Cat    50
## 4      Dog     1
## 5      Eel     1

df$group <- factor(df$group, levels = rev(levels(df$group)))

Make a pie chart:

ggplot(df, aes(x = "", y = value, fill = group)) +
  geom_bar(width = 1, stat = "identity") +
  coord_polar("y")

Add labels with geom_text():

library(ggrepel)

window <- function(x) {
  n <- length(x)
  res <- vector(length = n - 1)
  for (i in seq(n - 1)) {
    res[i] <- (x[i] + x[i+1]) / 2
  }
  return(res)
}

df$pos <- window(cumsum(c(0, df$value)))

ggplot(df, aes(x = "", y = value, fill = group))+
  geom_bar(width = 1, stat = "identity") +
  coord_polar("y", start = 0) +
  geom_text(aes(y = pos, x = 1.75, label = group)) +
  guides(fill = FALSE) +
  scale_fill_viridis_d() +
  theme_void()

Or use geom_text_repel():

library(ggrepel)

window <- function(x) {
  n <- length(x)
  res <- vector(length = n - 1)
  for (i in seq(n - 1)) {
    res[i] <- (x[i] + x[i+1]) / 2
  }
  return(res)
}

df$pos <- window(cumsum(c(0, df$value)))

ggplot(df, aes(x = "", y = value, fill = group))+
  geom_bar(width = 1, stat = "identity") +
  coord_polar("y", start = 0) +
  geom_text_repel(
    aes(y = pos, x = 1.5, label = group),
    size = 5, nudge_x = 0.2, min.segment.length = 1.25
  ) +
  guides(fill = FALSE) +
  scale_fill_viridis_d() +
  theme_void()

sessionInfo()

## R version 3.6.1 (2019-07-05)
## Platform: x86_64-apple-darwin15.6.0 (64-bit)
## Running under: macOS Catalina 10.15.3
## 
## Matrix products: default
## BLAS:   /Users/kamil/miniconda3/lib/libmkl_rt.dylib
## LAPACK: /Library/Frameworks/R.framework/Versions/3.6/Resources/lib/libRlapack.0.dylib
## 
## locale:
## [1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8
## 
## attached base packages:
## [1] stats     graphics  grDevices utils     datasets  methods   base     
## 
## other attached packages:
## [1] ggrepel_0.8.2 ggplot2_3.3.0
## 
## loaded via a namespace (and not attached):
##  [1] Rcpp_1.0.4        knitr_1.28        magrittr_1.5      tidyselect_1.0.0 
##  [5] munsell_0.5.0     viridisLite_0.3.0 colorspace_1.4-1  R6_2.4.1         
##  [9] rlang_0.4.5       stringr_1.4.0     dplyr_0.8.5       tools_3.6.1      
## [13] grid_3.6.1        gtable_0.3.0      xfun_0.12         withr_2.1.2      
## [17] htmltools_0.4.0   assertthat_0.2.1  yaml_2.2.1        digest_0.6.25    
## [21] tibble_2.1.3      lifecycle_0.2.0   crayon_1.3.4      farver_2.0.3     
## [25] purrr_0.3.3       glue_1.3.2        evaluate_0.14     rmarkdown_2.1    
## [29] labeling_0.3      stringi_1.4.6     compiler_3.6.1    pillar_1.4.3     
## [33] scales_1.1.0      pkgconfig_2.0.3

[shenweiyan]

It is really cool!

[olivroy]

Is there a trick to do better with longer labels, to ensure they don't go inside the pie chart?

library(ggplot2)
df <- data.frame(
  group = c("Antelope", "Bird", "Cat a longer label", "Dog", "Eel a longer label"),
  value = c(25, 25, 50, 1, 1)
)
df
#>                group value
#> 1           Antelope    25
#> 2               Bird    25
#> 3 Cat a longer label    50
#> 4                Dog     1
#> 5 Eel a longer label     1
 df$group <- factor(df$group, levels = rev(df$group))

library(ggrepel)

window <- function(x) {
  n <- length(x)
  res <- vector(length = n - 1)
  for (i in seq(n - 1)) {
    res[i] <- (x[i] + x[i+1]) / 2
  }
  return(res)
}

df$pos <- window(cumsum(c(0, df$value)))

ggplot(df, aes(x = "", y = value, fill = group))+
  geom_bar(width = 1, stat = "identity") +
  coord_polar("y", start = 0) +
  geom_text_repel(
    aes(y = pos, x = 1.5, label = group),
    size = 5, nudge_x = 0.2, min.segment.length = 1.25
  ) +
  guides(fill = "none") +
  scale_fill_viridis_d() +
  theme_void()

^{Created on 2024-04-30 with reprex v2.1.0}