annotate text on POSIXct x axis and Legend formating multiple vlines

Question

I have this plot:

library(ggplot2)
library(scales)
date_brake = "1 min"

t1 = as.POSIXct("2015-01-01 12:30:34",tz="GMT")
t1 <- as.POSIXct(format(t1),tz="UTC")
#attr(t1,"tzone") <- "America/New_York"
t1_numeric = as.numeric(t1)

t2 = as.POSIXct("2015-01-01 12:33:10",tz="GMT")
t2 <- as.POSIXct(format(t2),tz="UTC")
#attr(t1,"tzone") <- "America/New_York"
t2_numeric = as.numeric(t2)

t3 = as.POSIXct("2015-01-01 12:34:34",tz="GMT")
t3 <- as.POSIXct(format(t3),tz="UTC")
#attr(t1,"tzone") <- "America/New_York"
t3_numeric = as.numeric(t3)


dat = data.frame(x = as.POSIXct(c("2015-01-01 12:30:31","2015-01-01 12:35:30"),tz="GMT"), y = c(30,10)  )
ggplot(dat, aes(x=x, y = y))+geom_line()+
  scale_x_datetime(date_labels = "%H:%M:%S", breaks= date_breaks(date_brake)) +
  geom_hline(aes(yintercept = 15,linetype ="dashed"),color = "green") +
  geom_hline(aes(yintercept = 25,linetype ="dashed"),color = "blue") +
  geom_vline(aes(xintercept =  t1_numeric, linetype = "dotted"   ), color = "red"   ) +
  geom_vline(aes(xintercept =  t2_numeric, linetype = "dotted"   ), color = "red"   ) +
  geom_vline(aes(xintercept =  t3_numeric, linetype = "dotted"   ), color = "red")

I have 2 questions:

(1) How can I get the legend to show 3 legends: a legend for the blue line that shows a blue dashed line with title "Blue line", a legend for the green line that shows a green dashed line with title "Green line" and a 3rd legend that shows a red dotted line with title "Times"

(2) I would like to annotate or put text on the plot by the t1_numeric, t2_numeric and t3_numeric positions so I tried this:

geom_text() + 
  annotate("text", label = "t1", x = t1_numeric, y = 20, size = 8, colour = "red")+
  annotate("text", label = "t2", x = t2_numeric, y = 20, size = 8, colour = "red")+
  annotate("text", label = "t3", x = t3_numeric, y = 20, size = 8, colour = "red")

I would like to put the text "t1" at x = t1_numeric y = 20 I would like to put the text "t2" at x = t2_numeric y = 20 I would like to put the text "t3" at x = t3_numeric y = 20

But I get this error:

Error: Invalid input: time_trans works with objects of class POSIXct only

##################### UPDATE: the proposed solution almost works but when there is a "group" I get an error:

Error: Insufficient values in manual scale. 5 needed but only 3 provided.


dat = data.frame(x = as.POSIXct(c("2015-01-01 12:30:31","2015-01-01 12:35:30"),tz="GMT"), y = c(30,10), group = c("A","B") )

dat.hlines = data.frame(y = c(15,25, NA, NA, NA), 
                        label = c("Green Line", "Blue Line", "Times", "Times", "Times"), 
                        x = c(NA, NA, t1, t2, t3), 
                        label_2 = c(NA, NA, "t1", "t2", "t3"), 
                        label_xpos = c(t1, t1, t1, t2, t3)) # whatever the value linked to "Green" and "Blue" lines, label_2 (NA) wont be shown

ggplot(dat, aes(x, y, group = group)) +
   geom_point(aes (color = as.factor(group))) +
  scale_x_datetime(date_labels = "%H:%M:%S", breaks= date_breaks(date_brake)) +
  geom_hline(data = dat.hlines, aes(yintercept = y, color = label), linetype = "dashed") +
  geom_vline(data = dat.hlines, aes(xintercept = x, color = label), linetype = "dotted") + 
  scale_color_manual("Your title", values = c("Green Line" = "green", "Blue Line" = "blue", "Times" = "red")) +
  geom_text(data = dat.hlines, aes(label_xpos, label = label_2), y = 20, color = "red", hjust = -0.5)

Have you tried using 'scale_colour_manual' and/or 'scale_fill_manual'? — Edgar Santos

bVa bVa · Accepted Answer · 2017-03-31T08:22:51

A possible solution, creating a 2nd dataframe (dat.hlines) :

dat = data.frame(x = as.POSIXct(c("2015-01-01 12:30:31","2015-01-01 12:35:30"),tz="GMT"), y = c(30,10)  )

dat.hlines = data.frame(y = c(15,25, NA, NA, NA), 
label = c("Green Line", "Blue Line", "Times", "Times", "Times"), 
x = c(NA, NA, t1, t2, t3), 
label_2 = c(NA, NA, "t1", "t2", "t3"), 
label_xpos = c(t1, t1, t1, t2, t3)) # whatever the value linked to "Green" and "Blue" lines, label_2 (NA) wont be shown

ggplot(dat, aes(x, y)) +
  geom_line() +
  scale_x_datetime(date_labels = "%H:%M:%S", breaks= date_breaks(date_brake)) +
  geom_hline(data = dat.hlines, aes(yintercept = y, color = label), linetype = "dashed") +
  geom_vline(data = dat.hlines, aes(xintercept = x, color = label), linetype = "dotted") + 
  scale_color_manual("Your title", values = c("Green Line" = "green", "Blue Line" = "blue", "Times" = "red")) +
  geom_text(data = dat.hlines, aes(label_xpos, label = label_2), y = 20, color = "red", hjust = -0.5)

annotate text on POSIXct x axis and Legend formating multiple vlines

1 Answers