plotting some data to a figure with numerical data, one would expect the column border to line up with the grid. However, when plotting this data, you can see that there are some that line up correctly (10, 5), but others don't (2, 1).

Is this a bug or a feature?

Reproducible example

library(tidyverse, scales)

The data

x1 <- c("a", "b", "c", "d", "e")
y1 <- c(1, 10, 2, 1, 5)
xy <- data.frame(x1, y1)

The plot

xy %>% 
  ggplot(aes(x = fct_reorder(x1, desc(y1)),
             y = y1))  
  geom_col()  
  geom_text(aes(label = y1), vjust = 1.5, colour = "white") # to show the numbers

Some experiments

Correct

xy %>% 
  ggplot(aes(x = fct_reorder(x1, desc(y1)),
             y = y1))  
  geom_col()  
  scale_y_continuous(minor_breaks = seq(0, 10, .5))  
  # scale_y_continuous(labels = scales::number_format(accuracy = .5))  
  geom_text(aes(label = y), vjust = 1.5, colour = "white")

But then

Incorrect

xy %>% 
  ggplot(aes(x = fct_reorder(x1, desc(y1)),
             y = y1))  
  geom_col()  
  scale_y_continuous(minor_breaks = seq(0, 10, .5))  
  scale_y_continuous(labels = scales::number_format(accuracy = .5))  
  geom_text(aes(label = y), vjust = 1.5, colour = "white")

Also incorrect

xy %>%
  ggplot(aes(x = fct_reorder(x1, desc(y1)),
             y = y1))  
  geom_col()  
  scale_y_continuous(minor_breaks = seq(0, 10, 1),
                     labels = scales::number_format(accuracy = 1))  
  geom_text(aes(label = y1), vjust = 1.5, colour = "white")

CodePudding user response：

That 2 in yaxis is 2.5 and near 1 is 1.25 not 1.

xy %>% 
  ggplot(aes(x = fct_reorder(x1, desc(y1)),
             y = y1))  
  geom_col()  
  scale_y_continuous(breaks = seq(0,10,2))  
  geom_text(aes(label = y1), vjust = 1.5, colour = "white")

  xy %>% 
    ggplot(aes(x = fct_reorder(x1, desc(y1)),
               y = y1))  
    geom_col()

I don't know why you add accuracy = 1 but take a look at plot below.

xy %>% 
  ggplot(aes(x = fct_reorder(x1, desc(y1)),
             y = y1))  
  geom_col()  
  scale_y_continuous(breaks = seq(0,10,2))

CodePudding user response：

This is a rounding error caused by your scales_y_continuous call. Use

ggplot(xy,aes(x = fct_reorder(x1, desc(y1)),
           y = y1))  
  geom_col()  
  scale_y_continuous(breaks=c(0,2,5,8,10))  
  geom_text(aes(label = y1), vjust = 1.5, colour = "white")

To get what you want.