Re: Suggestion to improve usability of plot command

[Keir M. <ke...@cs...>]

> Keir Mierle wrote:
> >I have a simple suggestion to improve the usability of the plot command.
> >Currently, I am not a huge fan of the way point styles are specified; 
> 
> Not very surprisingly --- the syntax you use has never actually been 
> documented, and has been deprecated for a *long* time now.  The current 
> syntax, while still oriented towards numbers, is a lot clearer than

This was not obvious to me in the documentation.  After digging around, I found
an example of the new syntax hidden in the variable point size demo in the
gnuplot 4.2 examples.

Before I continue, I must say thank you for writing gnuplot, and for
documenting it. I realize documentation is a thankless job. It is odd to think
that the best comments one can hope for with documentation are none at all.

Now, having said that, let's take this from a new users (my) perspective. All
I want to accomplish is to control the scatter plot symbols.

   1) I go to gnuplot.info. I click on the obvious Documentation link (good).
   2) A page with a bunch of information comes up about the different formats
      available. Not clear exactly which link I should click; since I prefer
      searchable HTML for documentation, I click the HTML link under 'Official
      gnuplot Documentation'.
   3) In the official documentation, I accidentally page down past the table of
      contents, because it lacks numbers or subsections, which I expect in
      documentation table of contents.  I hit 'home' to go back to the top of
      the page when I realize I'm not finding what I want.
   4) I finally realize that the table of contents is the bulleted list 
      immediately following the big `gnuplot'. I click on Plotting.
   5) I see a bunch of text, none of which has any plots. There is no link to
      'plot' when the section mentions the plot command. Searching for 'plot'
      is ineffective, because the word is used so many times. At this point, I
      hit back a few times and go to the official gnuplot quick reference.
   6) After looking all over for an example with different points, I find, on
      the bottom of page 4, the following example:

          plot "data" with points 1 3

      My intuition says this is the command I want. Indeed, it is.

In all fairness, I went back and finally found the REAL table of contents,
which is above the 'gnuplot' table of contents and below the list of
contributors (in small text, with no title). I clicked Commands, then 'plot',
where it describes the plot command. Because I already knew I was looking for
'with', I clicked that. There it was. Yet, *still*, nowhere does it say 'to
plot with circles, use this style.' I had to do trial and error to find the
right symbol.

I understand that usability is hard. I am mailing the list with my experiences
in the hopes that gnuplot can improve, and the next person's experience will be
better. My father gave up on Gnuplot ages ago because he encountered similar
frustrations to my own; however, he silently moved on rather than engaging the
community.
 
> >gnuplot> plot 'file1' with points 4 3
> >gnuplot> plot 'file2' with points 1 4
> 
> The problem with both your suggestions:
> 
> >gnuplot> plot 'file1' with points 'red squares'
> >gnuplot> plot 'file2' with points 'blue crosses'
> >gnuplot> plot 'file1' with points 'orange octagons'
> [...]
> >The symbols are:
> >        's' : square
> >        'o' : circle
> >        '^' : triangle up
> 
> is the same: they completely ignore one central design principle of 
> gnuplot: script compatibility across terminal drivers.  Your proposal
> fails to address the question what gnuplot should do with a plot script 
> that requests some point symbol the current driver simply can't generate.

I address this in my other follow-up. I would also like to mention that I feel
when choices of symbol types are deliberate, it is unfortunate that gnuplot
does not guarentee the same symbols across terminals.

Gnuplot should simply make an expansive list of Standard Gnuplot Symbols, a
subset of which every terminal is required to implement.

Cheers,
Keir