Re: [Gnuplot-info] Managing long/complicated plot commands?

[Hernán De A. <var...@gm...>]

You may already had this suggestion, as in using variables, but consider 
that given the length and complexity of your command, it is perhaps a 
better idea to use a script to do all steps from building your set of 
plot instructions, writing them to a configuration file, and then 
running the gnuplot command. I do this all the time to a good effect.

/H.

Den 2026-03-29 kl. 11:49, skrev Bjorn Buckwalter:
> Thanks Jesper and Philpp. Jespers suggestion with variables can likely help
> – I will try it!
>
> FYI here is an example plot command that fails:
>
> ```
>    plot \
>      'world_110m.txt' using (lon($1)):(filter_lat($2)) with lines linecolor
> "gray" notitle , \
>      lat(0) with lines black dashtype 2 title "Equator" , \
>      lat(66.6) with lines black dashtype 5 title "Arctic/Antarctic circle", \
>      lat(-66.6) with lines black dashtype 5 notitle , \
>      for [orbit in orbits] \
>        'data/Report'.orbit.'.txt' using (lon($7)):(filter_lat($6)) \
>          with lines linecolor rgb next_color_t(n, 'cc') notitle, \
>      for [orbit in orbits] \
>        'data/Report'.orbit.'.txt' using (lon($7)):($3 == 2030 ?
> filter_lat($6) : NaN) \
>          with lines linecolor rgb next_color(n) title orbit, \
>      lat(lat1) black notitle  # edge of plot
> ```
>
> There is A LOT going on there with various custom functions, etc. I tried
> to make a minimal and “dependency-free” example but failed to reproduce the
> behavior. I could maybe try harder.
>
> Here is in any case the error from gnuplot. The command has been
> concatenated at all baskslashes except the last:
>
> ```
>    plot     'world_110m.txt' using (lon($1)):(filter_lat($2)) with lines
> linecolor "gray" notitle ,     lat(0) with lines black dashtype 2 title
> "Equator" ,     lat(66.6) with lines black dashtype 5 title
> "Arctic/Antarctic circle",     lat(-66.6) with lines black dashtype 5
> notitle ,     for [orbit in orbits]       'data/Report'.orbit.'.txt' using
> (lon($7)):(filter_lat($6))         with lines linecolor rgb next_color_t(n,
> 'cc') notitle,     for [orbit in orbits]       'data/Report'.orbit.'.txt'
> using (lon($7)):($3 == 2030 ? filter_lat($6) : NaN)         with lines
> linecolor rgb next_color(n) title orbit, \    lat(lat1) black notitle  #
> edge of plot
>
>
>
>
>
>
>
>
>     ^
> "$plot_polar" line 15: invalid character \
> ```
>
> There is nothing wrong with the backslash (no trailing spaces, etc.).
>
> If I change it as so (just shortening style definitions) it works:
>
> ```
>    set style data lines
>    plot \
>      'world_110m.txt' using (lon($1)):(filter_lat($2)) lc "gray" notitle , \
>      lat(0) black dt 2 title "Equator" , \
>      lat(66.6) black dt 5 title "Arctic/Antarctic circle", \
>      lat(-66.6) black dt 5 notitle , \
>      for [orbit in orbits] \
>        'data/Report'.orbit.'.txt' using (lon($7)):(filter_lat($6)) \
>          lc rgb next_color_t(n, 'cc') notitle, \
>      for [orbit in orbits] \
>        'data/Report'.orbit.'.txt' using (lon($7)):($3 == 2030 ?
> filter_lat($6) : NaN) \
>          lc rgb next_color(n) title orbit, \
>      lat(lat1) black notitle  # edge of plot
> ```
>
> All I did was remove `with lines` (using `set style data lines` instead and
> replace `linecolor` and `dashtype` with `lc` and `dt`, respectively. This
> is why I say it seems to be somehow related to the length/number of
> characters of a command.
>
> Thanks,
> Bjorn
>
>
> On Sun, Mar 29, 2026 at 5:28 AM Philipp K. Janert<ph...@ja...> wrote:
>
>> On Sat, 28 Mar 2026 22:13:40 +0100
>> Bjorn Buckwalter<bjo...@gm...> wrote:
>>
>>> HI all,
>> How long (in characters) are the command lines that
>> you are using? Mine frequently run long, and it has
>> never been a problem.
>>
>> Is it possible that you have problems with embedded
>> newlines, or that something goes awry if your command
>> line runs into a new line in your terminal?
>>
>> Best,
>>
>>                  Ph.
>>
>>> I rather often run into a problem of my plot commands being too long,
>>> typically resulting in a not-very-helpful error message such as:
>>>
>>> "$plot_polar" line 21: invalid character \
>>>
>>> It took a lot of head scratching to realize the root of the problem. I
>>> assume there are strong reasons for both the limitation on command
>>> length and the poor error message.
>>>
>>> I cannot be the only one running into this problem. The situation
>>> being what it is, what are the rest of you doing to manage when you
>>> run up against this limit? Replacing `linecolor` with `lc`, etc, will
>>> only get me so far and at the expense of readability.
>>>
>>> Many thanks,
>>> Bjorn
>>>
>>> _______________________________________________
>>> gnuplot-info mailing list
>>> gnu...@li...
>>> Membership management via:
>>> https://lists.sourceforge.net/lists/listinfo/gnuplot-info
>>
>>
>> --
>>
>> Philipp K. Janert
>> www.janert.me
>>
>>
>> _______________________________________________
>> gnuplot-info mailing list
>> gnu...@li...
>> Membership management via:
>> https://lists.sourceforge.net/lists/listinfo/gnuplot-info
>>
> _______________________________________________
> gnuplot-info mailing list
> gnu...@li...
> Membership management via:https://lists.sourceforge.net/lists/listinfo/gnuplot-info