Formatting x axis with different dates in ggplot2

Question

I am struggling to format the x-axis of a stacked area plot with ggplot2. This is my data:

df <- data.frame(
     Taxon = c("Others", "Dinos", "Diatoms", "Others", "Dinos", "Diatoms", "Others", "Dinos", "Diatoms", "Others", "Dinos", "Diatoms", "Others", "Dinos", "Diatoms", "Others", "Dinos", "Diatoms", "Others", "Dinos", "Diatoms", "Others", "Dinos", "Diatoms"),
     Abundance = c(14192, 120, 440, 6000, 80, 360, 25800, 4384, 169428, 879103, 2000, 52360, 213508, 22560, 470900, 472808, 11920, 316312, 81504, 6280, 15096, 50656, 11360, 43448),
     Date = c("05/01/2019", "05/01/2019", "05/01/2019", "09/03/2019", "09/03/2019", "09/03/2019", "11/04/2019", "11/04/2019", "11/04/2019", "01/05/2019", "01/05/2019", "01/05/2019", "01/06/2019", "01/06/2019", "01/06/2019", "01/07/2019", "01/07/2019", "01/07/2019", "01/08/2019", "01/08/2019", "01/08/2019", "01/09/2019","01/09/2019", "01/09/2019")
)

df %>% group_by(Date, Taxon) %>% summarise_all(sum) -> df1

ggplot(df1, aes(x=as.Date(Date, format="%d/%m/%Y"), Abundance, colour=Taxon, fill=Taxon)) + geom_area(stat="identity", position="stack") + labs(x = "", y = "") + scale_x_date(labels = date_format("%d/%m/%Y")) + theme(axis.text.x = element_text(angle = 45, vjust = 0.5))

This gives me the following plot:

My questions are now:

How do I get the x axis labels to correspond to the dates in df2$Date and not the first of the month?
I would like all dates to be visible on the x axis. I tried to use scale_x_continuous(labels=dates) with dates <- unique(df1$Date) but this gives me an error. How do I get it right?

I would very much appreciate any hints!

If you want to adjust the breaks (i.e. the values at which labels are shown) that's with the `date_breaks` argument, not the `date_labels` argument — camille, Jan 16 '20 at 15:49
Does this answer your question? [R: ggplot display all dates on x axis](https://stackoverflow.com/questions/41855673/r-ggplot-display-all-dates-on-x-axis) — Cole Robertson, Jan 16 '20 at 15:58

score 1 · Answer 1 · answered Jan 16 '20 at 15:53

Use the breaks argument

To change date frequency, you have to use the break argument on scale_x_date() function, like this:

+ scale_x_date(labels = date_format("%d/%m/%Y"), breaks = date_breaks("2 weeks"))

This is the complete code for a graph with 2 weeks break:

library(dplyr)
library(ggplot2)
library(scales)

df1 %>% ggplot(aes(
  x = as.Date(Date, format = "%d/%m/%Y"),
  Abundance,
  colour = Taxon,
  fill = Taxon
)) +
  geom_area(stat = "identity", position = "stack") +
  labs(x = "", y = "") +
  scale_x_date(labels = date_format("%d/%m/%Y"), breaks = date_breaks("2 weeks")) +
  theme(axis.text.x = element_text(angle = 45, vjust = 0.5))

Hope this helps.

Thanks for your help, but Jonathan's answer was what I needed. — wylierose, Jan 17 '20 at 08:41

Jonathan V. Solórzano · Accepted Answer · 2020-01-16T17:22:00.777

1

You should set the breaks argument in scale_x_date as the same object that you assigned to labels.

scale_x_date(labels = as.Date(df1$Date, format="%d/%m/%Y"), 
breaks = as.Date(df1$Date, format="%d/%m/%Y"))

edited Jan 16 '20 at 17:22

answered Jan 16 '20 at 15:58

Jonathan V. Solórzano

4,720
10
22

This is exactly what I wanted! Thank you so much! – wylierose Jan 17 '20 at 08:39

score 0 · Answer 3 · answered Jan 16 '20 at 15:55

Adjust the date_breaks argument in scale_x_date, ie.:

ggplot(df1, aes(x=as.Date(Date, format="%d/%m/%Y"), Abundance, colour=Taxon, fill=Taxon)) + 
  geom_area(stat="identity", position="stack") + labs(x = "", y = "") + 
  scale_x_date(labels = date_format("%d/%m/%Y"),date_breaks = '1 week') + 
  theme(axis.text.x = element_text(angle = 45, vjust = 0.5))

Formatting x axis with different dates in ggplot2

3 Answers3

Use the breaks argument