R help - Jun 2008 - Setting the xlab for 'the other' (upper) X axis?

I would like to set the 'xlab' on the 'upper' x axis. The
following code
shows roughly what I want by way of (one possible) expected behaviour.

par(mar=c(5.1, 4.1, 5.1, 2.1))
plot(rnorm(10), rnorm(10), xlab="the lower one")
axis(3, xlab="the upper one????")

There are various other ways that could be expected to work, but hopefully
the above is clear enough to show you what I want to achieve.

The following works, but is fragile (works without resizing the window of an
X11 device).

title(xlab="the upper one", line=-28)


Is there any better way to do it other than tinkering with 'line='?


Here is the same code as above but with comments just for reference.

# Give upper and lower margins an equal size
par(mar=c(5.1, 4.1, 5.1, 2.1))

# Plot (labeling the lower x axis)
plot(rnorm(10), rnorm(10), xlab="the lower one")

# Add the upper x axis (labeling fails!)
axis(3, xlab="the upper one????")

# Works but is fragile
title(xlab="the upper one", line=-28)

	[[alternative HTML version deleted]]

And the answer is...

mtext("the upper one?", side=3, line = par("mgp")[1])


2008/6/19 Dan Bolser <dan.bolser.r@googlemail.com>:
> I would like to set the 'xlab' on the 'upper' x axis. The
following code
> shows roughly what I want by way of (one possible) expected behaviour.
>
> par(mar=c(5.1, 4.1, 5.1, 2.1))
> plot(rnorm(10), rnorm(10), xlab="the lower one")
> axis(3, xlab="the upper one????")
>
> There are various other ways that could be expected to work, but hopefully
> the above is clear enough to show you what I want to achieve.
>
> The following works, but is fragile (works without resizing the window of
> an X11 device).
>
> title(xlab="the upper one", line=-28)
>
>
> Is there any better way to do it other than tinkering with 'line='?
>
>
> Here is the same code as above but with comments just for reference.
>
> # Give upper and lower margins an equal size
> par(mar=c(5.1, 4.1, 5.1, 2.1))
>
> # Plot (labeling the lower x axis)
> plot(rnorm(10), rnorm(10), xlab="the lower one")
>
> # Add the upper x axis (labeling fails!)
> axis(3, xlab="the upper one????")
>
> # Works but is fragile
> title(xlab="the upper one", line=-28)
>
>
>
	[[alternative HTML version deleted]]