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

[Bjorn B. <bjo...@gm...>]

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
>