[R] Re - segments within a lattice graph

[ripley@stats.ox.ac.uk]

On Mon, 6 Jan 2003 John.Gavin at ubsw.com wrote:

> The solution to my problem is to use
> 'lsegments' instead of 'segments' within lattice commands.
>
> (Although I wont forget again,
> a comment in the segments help file referring to 'lsegments'
> might help others not to make the same mistake in the future.)

*But* the segments help file is part of base R graphics, and xyplot and
lsegments are part of the recommended addon package lattice.  To be
consistent you would want us to document in base R all the places where
there are limitations of usage with addons (or recommended addons).
There would be an awful lot of those (including on all of the
graphics-related help pages).

Surely the answer is to read the documentation of the package you are
using to see *its* restrictions.  In your case you were using a panel
function in xyplot, and ?xyplot's panel argument does explicitly tell you

       There are also some grid-compatible replacements of base R graphics
       functions useful for this purpose, such as `llines'. (Note
       that the corresponding base R graphics functions like `lines'
       would not work.) These are usually sufficient to convert
       existing custom panel functions written for S-Plus.


-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
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