[R] Lattice xyplot log scale labels help!

Deepayan Sarkar deepayan.sarkar at gmail.com
Fri Sep 16 15:26:55 CEST 2011

On Fri, Sep 16, 2011 at 2:17 AM, Cram Rigby <cram.rigby at gmail.com> wrote:
> I have a problem with lattice log scales that I could use some help with.
> I'm trying to print log y-axis scales without exponents in the labels.
>  A similar thread with Deepayan' recommendation is here:
> http://tolstoy.newcastle.edu.au/R/e11/help/10/09/9865.html.  For
> example, this code using xyplot produces a logged y-axis but the
> labels  (e.g. "10^1.2") are not very user-friendly:
> xyplot(24:300~24:300, scales=list(y=list(log=T)))
> So, trying another y.scale.component function, we get something more
> agreeable for y-axis scale labels:
> xyplot(24:300~24:300, scales=list(y=list(log=T)), yscale.components =
> yscale.components.log10.3)
> However, my problem is that occasionally I'll have to plot data that
> doesn't quite "work".  For example, in the following example, I only
> get one y-axis scale label:
> xyplot(11:30~11:30, scales=list(y=list(log=T)), yscale.components =
> yscale.components.log10.3)
> or worse, no y-axis scale labels:
> xyplot(11:19~11:19, scales=list(log=T), yscale.components =
> yscale.components.log10.3)
> What would be most helpful is if someone can show me how to use an
> xyplot y-scale function to mimic log y-scale labels generated with the
> standard plot command.  This seems to work regardless of the
> underlying data range:
> plot(11:30,11:30,log = "y")
> plot(24:300,24:300,log="y")

That is because the standard graphics log-axis rules (which is
codified in axTicks(), and depends critically on par("yaxp")) is more
sophisticated than latticeExtra:::logTicks() (which was originally
written as a proof-of-concept demo).

To make logTicks() equally sophisticated, we need to replicate the
logic used to compute par("yaxp") (in src/main/graphics.c, I think),
which is doable, but not trivial.


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