[R] ggplot2 - geom_text() with date as x-axis

John Kane jrkrideau at inbox.com
Thu Jul 30 17:23:55 CEST 2015


I am trying to annotate a graph using geom_text() and I seem to be misunderstanding how to use a date in the co-ordinates---or, at least, I think that is the problem. Code is below.

Can anyone give me a suggestion of where I am going wrong?

Thanks,
John

John Kane
Kingston ON Canada
###===========================================
ibrary(ggplot2)
library(lubridate)
ins  <-  structure(list(td = structure(c(1437804720, 1437824100, 1437836220, 
1437851580, 1437863460, 1437878640, 1437890640, 1437904800, 1437918240, 
1437926100, 1437941340, 1437951240), tzone = "UTC", class = c("POSIXct", 
"POSIXt")), glucose = c(328L, 390L, 358L, 387L, 440L, 328L, 365L, 
450L, 467L, 477L, 408L, 457L), dose = c(NA, 0.5, NA, NA, 0.5, 
NA, NA, 0.5, NA, NA, NA, 0.5)), .Names = c("td", "glucose", "dose"
), row.names = c(NA, -12L), class = "data.frame")

anon  <- na.omit(ins)  # extract shots 

texdat =  ymd_hm("2015-07-26 20:09")

glucose  <-  ggplot(ins, aes(td, glucose)) + geom_point(colour = "red") + geom_line(colour = "blue")
p1  <-  glucose + annotate("text", x = texdat, y = 500, label = anon[ ,3 ], cex = 3) 
p1

# Now the problem
 p2  <-  p1 +  geom_text(x = texdat, y = 400 , size = 2,  label= "Glucose")
p2
###=============================================

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