在ggplot2中用不同日期格式化x轴

Question

我正在努力用 ggplot2 格式化堆积面积图的 x 轴。这是我的数据：

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))

这给了我以下情节：

我现在的问题是：

1. 如何让 x 轴标签与 df2$Date 中的日期而不是当月的第一天相对应？
2. 我希望所有日期都在 x 轴上可见。我尝试使用scale_x_continuous(labels=dates) dates <- unique(df1$Date) 但这给了我一个错误。如何正确处理？

我将非常感谢任何提示！

Answer 1

您应该将scale_x_date 中的breaks 参数设置为您分配给labels 的同一对象。

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

Answer 2

调整scale_x_date中的date_breaks参数，即：

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))

Answer 3

使用中断参数

要更改日期频率，您必须在 scale_x_date() 函数上使用 break 参数，如下所示：

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

这是带有2 weeksbreak 的图表的完整代码：

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))

希望这会有所帮助。