gnuplot-info

[Gnuplot-info] streamline with gnuplot ?

[Dellacherie S. <del...@CR...>]

Hello,

To obtain streamline with gnuplot, I use the command lines :

set xrange [-1:1]
set yrange [-1:1]
set arrow from 0,0 to 0.5,0.5
plot (0)
unset arrow
set xrange [*:*]
set yrange [*:*]

The problem is that I do not know how to do without the command line=20
"plot(0)".

Indeed, without this command, I cannot see the arrow on my x11 terminal.

What is the right way to obtain the arrows on my x11 terminal (i.e.=20
without "plot(0)") ?

Thank you for your help.

St=E9phane

Re: [Gnuplot-info] streamline with gnuplot ?

[Hans-Bernhard B. <br...@ph...>]

Dellacherie Stephane wrote:

[...]

> Indeed, without this command, I cannot see the arrow on my x11 terminal.
> 
> What is the right way to obtain the arrows on my x11 terminal (i.e. 
> without "plot(0)") ?

None.  Arrows are meant to be part of a plot, in gnuplot.  That's why 
the command is "set" arrow, not "draw arrow" or whatever --- arrows are 
part of the description of the plot you set up with various gnuplot 
"set" commands, which will then get executed for all subsequent "plot", 
"splot" and "replot" commands.

If you don't need an arrowhead, it may be that

	plot '-' w l
  	  0 0
	  0.5 0.5
	 E

is useful to you.  See "help datafile special" to see how this works.

Re: [Gnuplot-info] streamline with gnuplot ?

[Mike B. <mba...@uk...>]

St=E9phane,

I'm not sure that I fully understand what you want to do, but assuming that=
=20
you are trying to plot a series of vectors (which represent stream lines?),=
=20
then try someting like the following:

plot 'stream.dat' u 1:2:3:3 w vector

where the file 'stream.dat' contains=20

four columns of data corresponding to the x, y, delta_x and delta_y=20
coordinates of the arrows. I've used this to produce hydrological routing=20
networks (small example attached). It's also possible to drape flow lines,=
=20
such these, over a 3D surface.

Good luck,

Mike

> To obtain streamline with gnuplot, I use the command lines :
>
> set xrange [-1:1]
> set yrange [-1:1]
> set arrow from 0,0 to 0.5,0.5
> plot (0)
> unset arrow
> set xrange [*:*]
> set yrange [*:*]
>
> The problem is that I do not know how to do without the command line
> "plot(0)".
>
> Indeed, without this command, I cannot see the arrow on my x11 terminal.
>
> What is the right way to obtain the arrows on my x11 terminal (i.e.
> without "plot(0)") ?