Legend issue with ggplot2

Thanks Hadley,

I've been struggling with this all afternoon. But now it's working
again. Since I'm using it in a script, the few extra lines don't bother
me that much.

Thierry

------------------------------------------------------------------------
----
ir. Thierry Onkelinx
Instituut voor natuur- en bosonderzoek / Research Institute for Nature
and Forest
Cel biometrie, methodologie en kwaliteitszorg / Section biometrics,
methodology and quality assurance
Gaverstraat 4
9500 Geraardsbergen
Belgium
tel. + 32 54/436 185
Thierry.Onkelinx at inbo.be
www.inbo.be

Do not put your faith in what statistics say until you have carefully
considered what they do not say.  ~William W. Watt
A statistical analysis, properly conducted, is a delicate dissection of
uncertainties, a surgery of suppositions. ~M.J.Moroney

-----Oorspronkelijk bericht-----
Van: hadley wickham [mailto:h.wickham at gmail.com]
Verzonden: maandag 3 september 2007 15:15
Aan: ONKELINX, Thierry
CC: r-help at stat.math.ethz.ch
Onderwerp: Re: [R] Legend issue with ggplot2

On 9/3/07, ONKELINX, Thierry <Thierry.ONKELINX at inbo.be> wrote:

Dear useRs,

I'm struggling with the new version of ggplot2. In the previous
version I did something like this. But now this yield an

error (object "fill"

not found).

library(ggplot2)
dummy <- data.frame(x = rep(1:10, 4), group = gl(4, 10)) dummy$y <-
dummy$x * rnorm(4)[dummy$group] + 5 * rnorm(4)[dummy$group]

dummy$min

<- dummy$y - 5 dummy$max <- dummy$y + 5 ggplot(data =

dummy, aes(x =

x, max = max, min = min, fill = group)) +
geom_ribbon() + geom_line(aes(y = max, colour = fill)) +
geom_line(aes(y = min, colour = fill))

Strange - I'm not sure why that ever worked.

When I adjust the code to the line below, it works again. But this
time with two legend keys for "group". Any idea how to display only
one legend key for group? The ggplot-code aboved yielded

only on legend key.

ggplot(data = dummy, aes(x = x, max = max, min = min,

colour = group,

fill = group)) + geom_ribbon() + geom_line(aes(y = max)) +
geom_line(aes(y = min))

You can manually turn off one of the legends:

sc <- scale_colour_discrete()
sc$legend <- FALSE
.last_plot + sc

It's not very convenient though, so I'll think about how to
do this automatically.  The legends need to be more
intelligent about only displaying the minimum necessary.

Hadley