Re: gnuplot commands

[Matthias Brennwald]

On 06.08.2007, at 19:07, address@hidden wrote:

> Message: 1
> Date: Sun, 5 Aug 2007 14:25:59 -0700
> From: "Krishna Mohan Gundu" <address@hidden>
> Subject: gnuplot commands
> To: address@hidden
> Message-ID:
>         <address@hidden>
> Content-Type: text/plain; charset=ISO-8859-1
>
> Hi,
>
> Is there documentation on how to use gnuplot commands from octave? For
> example what is the equivalent of plot(x, y)?
>
> I would like to position the legend at a specific point on the plot. I
> have had some success, although I have no clue what is happening. I
> tried
>
> ps = get(gcf()).__plot_stream__;
> fputs(ps, "set key x,y \n");
> fputs(ps, "replot \n");
>
> and then reissue the plot() command again. Sometimes it works,
> sometimes it does not. Furthermore the legend position does not seem
> to be preserved on print, as it is not saved as an axis property. I
> tried setting an axis property as
>
> get(gca()).legpos = [x,y]
>
> and reuse it in __go_plot_axes__ but the value is not preserved.
>
> Any pointers and help is appreciated.
>
> cheers,
> Krishna.

Dear Krishna

the short answer is that you should not use gnuplot commands directly  
from Octave (there are several reasons for that, and it boils down to  
the fact that Octave aims to become Matlab compatible for the  
plotting stuff -- and Matlab has no gnuplot). Others may have longer  
answers, and the answer will also depend on the Octave version you use.

Apart from that:

1. Octaves 'legend' command has some options that allow you to set  
the position of the legend (type 'help legend' to the Octave prompt).

2. If you can't produce the plot you need from within Octave I'd  
suggest to save the data to a file (e.g. a text file) and plot it  
using gnuplot direclty. You may also put your gnuplot commands into a  
script file and call this script from within Octave to automate the  
process (take a look at Octaves 'system' command).

3. A quick and very dirty solution would be to use the  
__gnuplot_set__ and __gnuplot_raw__ commands. But you really should  
not rely on these commands to behave the same in different versions  
of Octave, and I take these commands will not be present in some  
future version of Octave.

4. Use a different plotting engine than gnuplot (e.g. octplot,  
octaviz, jhandles, etc.).

Cheers,
Matthias


-------
Matthias Brennwald
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address@hidden