How to change the positions of numbers on the x-axis in geom_bar()

Question

First, sorry for my bad english :( .

I have a question to the geom_bar: In my plot, the numbers are in the middle of a bar. For example, there appears to be nearly 50'0000 trees (Bäume) with IBaum = 5, but in realitythere are nearly 50'000 trees BETWEEN 0 and 5.

So my Question is: How can I change the position of the numbers in the x-axis?

my current code is:

p1 = ggplot(data = plotdat, 
            aes(x = factor(IB), y = Anzahl, fill = factor(PFT, levels = c(1,2,3,4)))) +
  geom_bar(stat = "identity", width = 0.8, position = "stack")+
  labs(title = TeX(paste("Anzahl der Bäume mit Wachstum $\\geq$ 0 zu $I_{Baum}$", 
                         sep = "" )), 
       x = TeX(paste("$I_{Baum} $", "$\\lbrack$%$\\rbrack$", "aus Inventur", invn[1], 
                     sep = " ")), 
       y = TeX("Anzahl der Bäume mit Wachstum $\\geq$ 0")) +
  scale_fill_manual("PFT", 
                    values = c("#95C11F", "#788938", "#243B0B", "#006633"), 
                    labels= c(1,2,3,4)) +
  theme_minimal(base_size = 14)

Welcome to S.O.! To make easier help you, you should provide some data to reproduce your code, similar to yours. This means you can post the result of `dput(plotdat)` if you can share your original data or create some fake data similar to yours and post them. — s__, Aug 13 '18 at 08:09

score 0 · Answer 1 · answered Aug 30 '18 at 16:01

If your x-axis is continuous (rather than discrete), you can position breaks at non-integer positions. Here's a toy dataset for illustration:

data <- mtcars %>% mutate(x = factor(cyl)) %>% count(x)

> data
# A tibble: 3 x 2
       x     n
  <fctr> <int>
1      4    11
2      6     7
3      8    14

The x variable is a factor here (corresponding to x = factor(IB) in your code). If we plot it as is, the labels would be centered at the middle of each bar. However, if we convert the x variable back to a numeric value, we can specify breaks in the following manner, which inserts a "0" label at the start (x = 0.5), & shifts all other labels rightwards by 0.5:

ggplot(data, 
       aes(x = as.integer(x), y = n)) + 
  geom_col() +
  scale_x_continuous(breaks = c(0.5, 0.5 + seq_along(levels(data$x))),
                     labels = c("0", levels(data$x))) +
  theme_minimal()

How to change the positions of numbers on the x-axis in geom_bar()

1 Answers1