[R] changing number of axis

[Dan Kortschak]

Hi Deepayan,

Thanks for that, I had a think (a few hour too late) and came to the
same conclusion. I had wanted to have vertical bars for each of the data
points, I have gone to a straight xyplot and this shows other intersting
information - maybe I want to be able to do both point and bar plots
(the bars show gaps in the bins nicely where the points don't).

I'm thinking there is probably a better way to do it that what I was
trying, a vertical line from y=0 to y=binvalue for each represented bin
seem most sensible, but I'm not sure how to go about this.

thanks
Dan


On Tue, 2009-09-29 at 22:59 -0700, Deepayan Sarkar wrote:
> On Wed, Sep 16, 2009 at 2:02 PM, Dan Kortschak
> <dan.kortschak at adelaide.edu.au> wrote:
> > 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).
> 
> Probably all 2500 of them.
> 
> > 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.
> 
> Basically, barchart has to be convinced that the limits are numeric.
> There are various ways to do that; the simplest is to provide a
> numeric 'xlim', e.g.,
> 
> df <- data.frame(y = runif(100), x = gl(100, 1))
> barchart(y ~ x, df, origin = 0)
> barchart(y ~ x, df, origin = 0, xlim = c(0, 101))
> 
> However, you should also rethink the use of barchart for a 2500-level
> factor; at a minimum, consider something like
> 
> xyplot(y ~ as.numeric(x), df, type = "h")
> 
> -Deepayan