can't change month number to month name using scale

This is my dataset:

temperature <- data.frame(
  stringsAsFactors = FALSE,
  Year= c(1998,1998,1998,1998,1998,1998,1998,1998,1998,1998,1998,1998,1999,1999,1999,1999,1999,1999,1999,1999,1999,1999,1999,1999,2000,2000,2000,2000,2000,2000,2000,2000,2000,2000,2000,2000,2001,2001,2001,2001,2001,2001,2001,2001,2001,2001,2001,2001,2002,2002,2002,2002,2002,2002,2002,2002,2002,2002,2002,2002),
  Month = c(1,2,3,4,5,6,7,8,9,10,11,12,1,2,3,4,5,6,7,8,9,10,11,12,1,2,3,4,5,6,7,8,9,10,11,12,1,2,3,4,5,6,7,8,9,10,11,12,1,2,3,4,5,6,7,8,9,10,11,12),
  Temperature = c(5,6,7,12,15,16,27,28,22,10,11,6,6,6,7,13,16,15,25,26,24,12,11,4,5,6,7,12,15,17,28,30,22,10,11,7,7,7,7,12,18,17,25,24,20,3,3,4,5,6,7,12,15,16,27,28,22,10,11,6),
  check.names = FALSE
)

temperature$date = as.Date(paste(temperature$Year, temperature$Month,1), format = "%Y %m %d")

This is the code I used

ggplot(temperature,
       aes(
         x = date,
         y = Temperature,
         colour=as.factor(Month),
         group=1
       ))  
  geom_line()  
  ggtitle("Time series")  
  scale_x_date(
    date_breaks = "year", 
    date_labels = "%Y", 
    date_minor_breaks = "month"
  )  
  xlab("Year")  
  ylab("Temperature")

Now the months were in number and not in name I used that code

ggplot(temperature,
       aes(
         x = date,
         y = Temperature,
         colour=as.factor(Month),
         group=1
       ))  
  geom_line()  
  ggtitle("Time series")  
  scale_x_date(
    date_breaks = "year", 
    date_labels = "%Y", 
    date_minor_breaks = "month", labels=month.abb
  )  
  xlab("Year")  
  ylab("Temperature")

But seems not work. I thougt that I have to change something in scale_x_date?

How can I change that month names came into the legend?

The problem is that the legend shows month number instead of month name

CodePudding user response：

For a color scale, I would specify the labels when you convert month to factor:

ggplot(temperature,
       aes(
         x = date,
         y = Temperature,
         colour=factor(Month, levels = 1:12, labels = month.abb),
         group=1
       ))  
  geom_line()  
  ggtitle("Time series")  
  scale_x_date(
    date_breaks = "year", 
    date_labels = "%Y", 
    date_minor_breaks = "month"
  )  
  labs(
    x = "Year",
    y = "Temperature",
    color = "Month"
  )

CodePudding user response：

If you want month abbreviations to appear in the legend, you'll need to modify the variable you are using to set the color. you call as.factor(Month) in your code which makes it a factor with levels 1 through 12. Changing to factor(Month, labels = month.abb) will update your legend. Note you could make this more readable by performing this factoring step on the data before plotting.

ggplot(temperature,
   aes(
     x = date,
     y = Temperature,
     colour=factor(Month, labels = month.abb),
     group=1
   ))  
geom_line()  
ggtitle("Time series")  
scale_x_date(
date_breaks = "year", 
date_labels = "%Y", 
date_minor_breaks = "month"
)  
xlab("Year")  
ylab("Temperature")