label geom_hline

[Jeroen]

I am looking for a way to add a label to an horizontal line over a
qplot. Is this possbile? For example, i use:

print(myPlot + geom_hline(yintercept=100,colour="red"));

And then I want to add a little title, preferebly just above the red
line on the left side in the plot, that says something like "Current
value".

[smu]

try:
+ annotate("text",x,y,label)

regards,
stefan

[Jeroen Ooms]

Thank you! Is there an easy way to annotate a text in for example the upper left corner of my plot? I have difficulties arranging this with x and y, because both scales are highly variable, and x is a date. Furthermore positioning of the text seems to depend on the size of the output device. 

Jeroen

2009/8/5 smu <s...@z107.de>

[hadley wickham]

It's not super easy, but it is possible. A reproducible example would
make it possible to suggest solutions.

Hadley

--
http://had.co.nz/

[Jeroen Ooms]

Allright. For example, try this code:

library(ggplot2);
myData <- read.csv("http://ichart.finance.yahoo.com/table.csv?s=GOOG&d=7&e=11&f=2009&g=d&a=7&b=19&c=2004&ignore=.csv",header=T);
myData$Date <- as.Date(myData$Date);
qplot(Date,Close,data=myData,geom='line');

Now I would like an annotation somewhere, for example in the left top
corner of the graph, that displays the result of Sys.time() (i.e. the
time at which the plot was made).



2009/8/11 hadley wickham <h.wi...@gmail.com>

[hadley wickham]

Something like this?

qplot(Date,Close, data = myData, geom = 'line') +
annotate("text", max(myData$Date), max(myData$Close),
label = Sys.time(), hjust = 1))

Hadley

--
http://had.co.nz/