[R] Surprise when mapping matrix to image

Deepayan Sarkar deepayan at cs.wisc.edu
Fri Aug 27 05:16:23 CEST 2004

Quoting "Richard A. O'Keefe" <ok at cs.otago.ac.nz>:

> Deepayan Sarkar <deepayan at cs.wisc.edu> wrote:
>  You seem to be thinking that Prof Ripley's solution had
>  something to do with image().
> "Glynn, Earl" <EFG at Stowers-Institute.org>
> could certainly be excused for thinking so, because
> what Prof Ripley wrote included this:
>  > > Did you try reading the help for image?  You don't seem to 
>  > > understand it if you actually did.
> That certainly sounds to me as though the answer should have been
> obvious from ?image

I agree with you that the issues are related, but your (edited) quoting is
misleading. I interpret Prof Ripley's comment as implying that reading ?image
would tell the user what happens when he calls image(x). This is distinct from
how to manipulate a matrix, which is what t(x)[ncol(x):1, ] is doing. It
doesn't seem obvious to me that this information should be in ?image, and I
still don't see how Prof Ripley's comment suggested that it was. Anything but
the most trivial use of S involves combining different ideas. One can hardly
expect all possible interactions to be documented.

Of course, documentation can always use improvements (and the rest of your
comments on ?image are all valid), and it would be nice to anticipate
frequently faced problems and offer solutions preemptively, but that's a
different issue.


More information about the R-help mailing list