removing geom_text redundancies

[Avram Aelony]

Hello,

I'm getting repeated labels (one per each level in variable) where one
would suffice: e.g. qplot( data=m, x=date, y=value, colour=variable,
label=major_event_desc ) + scale_y_continuous(formatter = "comma") +
geom_text( angle=90, size=3, colour='purple' ) +stat_smooth()

For example, with 2 levels of variable, I get 2 lines but also 2
overlapping indications of "independence day" on july 4th...

Is there any way to specify that the label should occur exactly once?

Here is a reproducible example:

data(economics)
m <- melt(data=economics[, c(1,2,4,5,6)], id.vars=c('date') )
m$idates <- ifelse(m$date=="1987-07-31", "random date of importance",
"")
qplot(data=m, x=date, y=value, colour=variable, geom=c('line','point'),
label=idates )+ geom_text( angle=90, size=4, colour='purple' ) +
stat_smooth()

Notice that the text "random date of importance" is repeated and
superimposed on itself once for each level of "variable" (i.e. pce,
psavert,
uempmed, unemploy ) making it unreadable. It would be great to have
something that indicates that it should be rendered only if it has
not been
rendered already.

Best regards,
Avram

[baptiste auguie]

Hi,

Can you not use annotate?

date = "1987-07-31"
condition = m$date==date

qplot(data=m, x=date, y=value, colour=variable, geom=c('line','point')) +
annotate("text", x=unique(m$date[condition]),y=0, label="random date
of importance",
angle=90, size=4, colour='purple' , hjust = 0)


HTH,

baptiste

[Avram Aelony]

I don't think so. The example is only meant to illustrate (pun
intended) the point... In effect, the labels come from a separate
data set full of such dates and the mechanism produces many graphs in
an automated fashion.

It would be great to instruct geom_text to do it's work only for the
first level of the colour=variable...

-A

[hadley wickham]

> Notice that the text "random date of importance" is repeated and
> superimposed on itself once for each level of "variable" (i.e. pce,
> psavert,
> uempmed, unemploy ) making it unreadable.  It would be great to have
> something that indicates that it should be rendered only if it has
> not been
> rendered already.

Only plot the data that you want in the text layer:

library(ggplot2)

m <- melt(data=economics[, c(1,2,4,5,6)], id.vars=c('date') )

imp_date <- subset(m, date == "1987-07-31" & variable == "pce")
imp_date$label <- "My important date"

ggplot(m, aes(date, value)) +
geom_line(aes(colour = variable)) +
geom_point(aes(colour = variable)) +
geom_text(aes(label = label), data = imp_date, angle = 90, size = 4)

Hadley

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

[Avram Aelony]

Thanks for this...
Regards,
-Avram