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

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.

geom_bar

Bäume

IBaum = 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)


dput(plotdat)

1 Answer
1

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:

x = factor(IB)

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()


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