Re: docs issues

[Ethan M. <merritt@u.washington.edu>]

On Thursday 15 February 2007 13:26, Petr Mikulik wrote:
>   There was some discussion on this list about the differences of
> 	splot 'bla' vs splot 'bla' using 1:2:3
>   but I cannot find it in the docs. Could somebody summarize it there,
>   and cross-link it with "help missing"?

Not sure what you mean.
The existing section for "help missing" explains what happens when
not all columns on a datafile line are usable.  The 3D splot case
is they same:  If all lines have at least the first 3 columns usable,
then "splot with <foo>" is the same as "splot using 1:2:3 with <foo>".

However, if some of the lines contain only 2 readable entries,
then "splot using 1:2:3 with <foo>" will work as expected by treating
the defective lines as "missing".
In this case "splot with <foo>" is not usable, because the plot style
is re-evaluated for each line and lines with only 2 entries can
switch the plotting style in mid-plot, yielding garbage.

This should probably be considered a bug in gnuplot, but it is not
at all clear what the proper fix is other than to recommend always
giving an explicit "using 1:2:3".


>   Further, I propose to label "help using" by "help nan" as well.

help gnuplot-defined NaN       (at least, that's where "pi" is explained)

-- 
Ethan A Merritt                                 Courier Deliveries: 1959 NE Pacific
Dept of Biochemistry    M/S 357742
Health Sciences Building
University of Washington - Seattle