如何在 ggplot2 每小时 plot Posix 数据？

Question

I have a dataframe:

bvar time
0.000000000 2003-03-14 19:00:00
0.200000000 2003-03-14 20:00:00
0.044000000 2003-03-14 21:00:00

Here, time is POSIXct:

str(tsdat$time)
 POSIXct[1:193], format: "2003-03-14 19:00:00" 

When I plot it, I want to control the x-axis by showing every hour:

ggplot(ts) +
  geom_line(aes(x=time, y=bvar))+
  theme(axis.text.x = element_text(angle = 0, hjust = 1))+
  scale_x_date(labels=date_format("%Y %H:%M")) + 
  ylab('BVAR [mm]')

ERROR

Error: Invalid input: date_trans works with objects of class Date only

How can I make this hourly? In another question, they suggested using as.Date . But this doesn't work for me as my data is for 2 days only.

Answer 1

I think you can use scale_x_datetime for POSIXct instead of scale_x_date . To get hourly breaks on the xaxis, also add breaks = "1 hour" .

library(ggplot2)
library(scales)

ggplot(ts) +
  geom_line(aes(x=time, y=bvar))+
  theme(axis.text.x = element_text(angle = 0, hjust = 1))+
  scale_x_datetime(labels=date_format("%Y %H:%M"), breaks = "1 hour") + 
  ylab('BVAR [mm]')

Output

Data

ts <- structure(list(bvar = c(0, 0.2, 0.044), time = structure(c(1047690000, 
1047693600, 1047697200), class = c("POSIXct", "POSIXt"), tzone = "")), row.names = c(NA, 
-3L), class = "data.frame")