labelling graph axes: sub/superscript

Dear r list,

I am having problems with superscripts and subscripts when labelling
axes on graphs. I am trying to get the following label onto my y
axis : Anet  (umol m-2 s-1). I am using the following code:

plot(SM,PN,pch=16,xlim=c(0,40),ylim=c(0,25),ylab=ytxt,xlab="soil

moisture content (% vol.)",
cex.lab=0.8,font.lab=1,bty="l",cex.axis=0.7,las=1)

ytxt=expression(""*A[net]*"  (umol  "*m^-2*" "*s^-1*")")

Is it possible to get only Anet  in italics in this label?
Additionally I find that the font.lab command does not work with axes
containing sub/superscripts so you are forced to use all the default
settings for you two axes to look the same. Does anyone know how I can
correct this?

dat <- data.frame(x = rnorm(100), y = rnorm(100))
plot(y ~ x, data = dat,
     ylab = expression(italic(Anet) ~~ (mu*mol ~ m^{-2} ~ s^{-1}))) 

[the double ~~ is there to add a bit of extra spacing - the "t" looked
too close to the "(" with just one ~]

In these cases you are using plotmath, so reading ?plotmath is a must.
It contains a section on fonts and how to change them to different
families, but all font.lab does is switch between bold, plain italic
etc., which can all be done using things like italic() as documented
in ?plotmath.

Perhaps you can explain better with reproducible code what you want to
do or find annoying that is not covered in ?plotmath if the above
doesn't answer/help with the last part of your post?

HTH

G

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 Dr. Gavin Simpson             [t] +44 (0)20 7679 0522
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