[R] changing number of axis

[Dan Kortschak]

Hi, I trying to produce a bar chart describing hits to specific bins by
chromosome for a large data set (I am asking here because
experimentation with options is precluded due to this - generating the
figure takes about an hour):

barchart(hits~bin|chromosome, data=hits, horizontal=FALSE, origin=0,
lab=c(3,10), layout=c(1,5,5), strip=strip.custom(style=3, bg="grey90",
par.strip.text=list(cex=0.5)), as.table=TRUE);

I have about 2500 bins for the largest factor and barchart is drawing
tick labels for a substantial proportion of these (how many, I can't see
since due to the density of the labels).

My question is how I can get a sane number of labels along the x axis
(about 5-10 would be good). I suspect that 'scales' might be the way to
go, but I can't see an obvious option to do this.

thanks
-- 
Dan Kortschak <dan.kortschak at adelaide.edu.au>