[Rd] Mosaicplot coloring (PR#8537)

[Greg Kochanski]

Achim Zeileis wrote:
> On Sun, 29 Jan 2006 greg.kochanski at phon.ox.ac.uk wrote:
> 
> 
>>Full_Name: Greg Kochanski
>>Version: 2.2.1
>>OS: Debian Linux (testing)
>>Submission from: (NULL) (212.159.16.190)
>>
>>
>>mosaicplot(x, shade=TRUE) is intended to color the blocks
>>blue if they are more common than one might expect
>>and red if they are rarer than one might expect.
>>
>>Unfortunately, if a block is much rarer than expected,
>>it is so narrow that one cannot see the red.
> 
> 
> Where is the bug?? Please read Section 9 in
>   http://CRAN.R-project.org/doc/manuals/R-FAQ.html
> and also the posting guide at
>   http://www.R-project.org/posting-guide.html
> 

The bug is that the software produces results that could
lead to the wrong conclusion in a research paper,
or could lead the readers of the research paper to
an erroneous belief.  That sounds like a
relevant definition of a bug to me.

 From section  9:
> Finally, a command's intended definition may not be best for
 > statistical analysis. This is a very important sort of problem,
 > but it is also a matter of judgment.
 > > ... The manual's job is to make everything clear.
 > It is just as important to report documentation bugs
 > as program bugs....

 From my reading of section 9, this is a documentation bug.

...
> For an enhanced implementation of mosaic plots written in the grid
> graphics system, see the package "vcd" and the functions mosaic() and
> strucplot(). See the package vignettes for details on control of the
> graphical appearance and also for combining shading and significance
> testing. To overcome the problem of small cells, another approach is to
> plot expected instead of observed frequencies.
> Z


You shouldn't be telling this to me,
you should be putting it in the documentation where
it might help more than one person.
Putting a "see also" note in help(mosaicplot) that points
to the "vcd" package, and "mosaic" and "strucplot" functions
might be a solution to the problem.