R help - Apr 2004 - helps on levelplot

I'm a new user of levelplot, and are not familiar with the terminology 
very well. Is the bar alongside the levelplot indicating color or shade 
call "colorkey"? I have to adjust the size of its label, but
couldn't
make it so far. This is how I did:

levelplot(z~x*y, grid, at=seq(0,1,by=0.1), 
colorkey=list(labels=list(cex=2)))

But I got error message "Error in draw.colorkey(x$colorkey) : Object 
"at" not found". I tried to specify "at" in colorkey
too, but it didn't
help.

A second task I have to do is to add horizontal and vertical lines on 
the levelplots, just like the way that ablines() works for image(). 
ablines doesn't work for levelplot. Any help will be much appreciated.

On Tuesday 27 April 2004 16:43, Yan Wang wrote:
> I'm a new user of levelplot, and are not familiar with the
> terminology very well. Is the bar alongside the levelplot indicating
> color or shade call "colorkey"? I have to adjust the size of its
> label, but couldn't make it so far. This is how I did:
>
> levelplot(z~x*y, grid, at=seq(0,1,by=0.1),
> colorkey=list(labels=list(cex=2)))
>
> But I got error message "Error in draw.colorkey(x$colorkey) : Object
> "at" not found". I tried to specify "at" in
colorkey too, but it
> didn't help.
Looks like a bug. For a workaround, you need to specify at in the labels 
component, not in colorkey (both are allowed), e.g.

colorkey=list(labels=list(cex=2, at=<whatever>))
> A second task I have to do is to add horizontal and vertical lines on
> the levelplots, just like the way that ablines() works for image().
> ablines doesn't work for levelplot. Any help will be much
> appreciated.
Use panel.abline, in the same way panel functions work in all lattice 
functions. e.g.,

levelplot(matrix(1:20, 4, 5), 
          panel = function(...) {
              panel.levelplot(...)
              panel.abline(h = 3.2)
          })

Deepayan