删除ggplot y轴和第一个x值之间的间隙

Question

我需要删除x轴上1950之前的间隙。

我试图使用scale_x_continuous但这会导致：

Error: Discrete value supplied to continuous scale

我相信这一定有事情做与数据的日期格式。

实施例的数据：

x  y    date 
1 -631152000 -1.018 1950-01-01 01:32:40 
2 -628473600 -1.143 1950-02-01 01:32:40 
3 -626054400 -1.290 1950-03-01 01:32:40 
4 -623376000 -1.061 1950-04-01 01:32:40 
5 -620784000 -1.416 1950-05-01 01:32:40 
6 -618105600 -1.372 1950-06-01 01:32:40 
7 -615513600 -1.334 1950-07-01 01:32:40 
8 -612835200 -1.050 1950-08-01 01:32:40 
9 -610156800 -0.578 1950-09-01 01:32:40 
10 -607564800 -0.395 1950-10-01 01:32:40 

用于创建情节的代码：

Plot <- ggplot(d2,aes(x = date, 
       y = y)) + 
    geom_area(data=subset(d2, y<=0), fill="blue") + 
    geom_area(data=subset(d2, y>=0), fill="red") + 
    scale_y_continuous(name = "MEI")+ 
    xlab("Year")+ 
    theme(axis.text.y = element_text(size=24), 
     axis.text.x = element_text(size=24), 
     axis.title.y = element_text(size=24), 
     axis.title.x = element_text(size=24), 
     panel.background = element_blank(), 
     panel.grid.major = element_line(colour = "grey"), 
     strip.background = element_blank(), 
     panel.border = element_rect(colour = "black", fill = NA), 
     axis.line = element_line(colour = "black")) 

任何帮助，将不胜感激!!!

Answer 1

您可以使用scale_x_datetime的参数expand删除轴和数据的开始之间的空格。 （你也可以使用这scale_y（X）_continuous，和其他...）

# your data - tweaked to include pos/neg y values 
d2 <- read.table(text="x  y    date 
1 -631152000 -1.018 '1950-01-01 01:32:40' 
2 -628473600 -1.143 '1950-02-01 01:32:40' 
3 -626054400 -1.290 '1950-03-01 01:32:40' 
4 -623376000 -1.061 '1950-04-01 01:32:40' 
5 -620784000 -1.416 '1950-05-01 01:32:40' 
6 -618105600 1.372 '1950-06-01 01:32:40' 
7 -615513600 1.334 '1950-07-01 01:32:40' 
8 -612835200 1.050 '1950-08-01 01:32:40' 
9 -610156800 0.578 '1950-09-01 01:32:40' 
10 -607564800 0.395 '1950-10-01 01:32:40'", header=TRUE) 

# create date class and tag for y being pos/negative 
d2$date <- as.POSIXct(d2$date) 
d2$tag <- d2$y < 0 

library(ggplot2) 

ggplot(d2,aes(x = date, y = y, fill=tag)) + 
         geom_area() + 
         scale_y_continuous(name = "MEI")+ 
         scale_x_datetime(expand=c(0,0))