Re: Plotting date on xaxis

["Eric Schulte" <schulte.eric@gmail.com>]

Eric S Fraga <ucecesf@ucl.ac.uk> writes:

[...]
>
> I have narrowed down what causes the problem although I don't
> understand why (I haven't had any time to look at the elisp code).
> Basically, the problem with Johan's initial table was the extra empty
> row at the end:
>

Ah,

Thanks for isolating the issue.

It looks like the empty last row is tricking org-plot.el into thinking
that the entire Date column contains text labels, so it tries to use the
values of that column to label the data with xticlabels [1].  This is
useful for histograms such as the "Citas" graph in [2].

So all in all I'd say this is fine behavior for something like org-plot
which tries to guess the user's intentions.

Best -- Eric

>
> #+PLOT: title:"Weight" ind:1 deps:(2) type:2d with:linespoints set:"xdata time" set:"timefmt '%Y-%m-%d'" set:"yrange [90:]"
> |       Date |   Kg |
> |------------+------|
> | 2010-02-21 | 95.0 |
> | 2010-02-22 | 93.0 |
> | 2010-02-23 | 92.0 |
> | 2010-02-24 | 91.5 |
> | 2010-02-25 | 91.0 |
> | 2010-02-28 | 92.0 |
> |            |      |
>
> With the empty row there, the "using 1:2" option to the gnuplot plot
> command is not generated correctly, instead generating "using
> 1:xticlable(1)" which gnuplot doesn't like!  If the last row is
> deleted, everything works just fine (even if February doesn't have 29
> days in 2010 ;-).
>
> HTH,
> eric

Footnotes: 
[1]  http://www.gnuplot.info/docs/node135.html

[2]  http://orgmode.org/worg/org-tutorials/org-plot.php