From help-request at octave dot org Thu Jul 14 19:16:23 2005
Subject: Re: trouble reversing x-axis in octave
From: "Robert A. Macy" <macy at california dot com>
To: bode at ipac dot caltech dot edu
Cc: help at octave dot org
Date: Thu, 14 Jul 2005 17:11:31 -0700

I don't understand your problem since I don't use any of
those commands, and I have a lot of "reversed" ordinates.

However, if all else fails reverse them yourself

nuordinate=oldordinate(end+1-(1:end));

         - Robert -

On Thu, 14 Jul 2005 17:02:10 -0500
 Andy Boden <bode at ipac dot caltech dot edu> wrote:
> Dear All,
> 
> I am having trouble reversing the x-axis (i.e. displaying
> from a larger
> to a smaller value going left to right) on a plot
> generated by octave,
> and I'm wondering if anyone has either seen this same
> symptom or know
> what I am doing wrong.
> 
> Context dump:
> 
> I have developed an octave application that models
> astronomical
> photometry with template spectral energy distributions
> (SEDs).
> 
> I would like to produce a plot with two horizontal axes
> -- spectral
> wavelength on one horizontal axis (x2), and frequency on
> the other
> horizontal (x1) axis.  Of course, these two quantities
> are inversely
> related, so if one ascends left to right, the other must
> descend left to
> right.
> 
> I am running octave 2.1.71 (via RPM package), and gnuplot
> 4.0.0 on a
> Fedora Core 4 machine.
> 
> ---
> 
> Symptomology:
> 
> I try to do the right thing in terms of setting the
> ranges for the two
> axes (code extract):
> 
>   ## lMin & lMax in um
>   eval(sprintf('__gnuplot_set__ x2range
> [%f:%f]',lMin,lMax));
>   nuMin = cMKS / (lMin * 1e-6);
>   nuMax = cMKS / (lMax * 1e-6);
>   eval(sprintf('__gnuplot_set__ xrange
> [%f:%f]',nuMin,nuMax));
> 
>   __gnuplot_show__ x2range
>   __gnuplot_show__ xrange
> 
> Output from the show commands above suggest that all is
> as it should be:
> 
> 
> >      set x2range [ 0.115000 : 2.50000 ] noreverse
> nowriteback
> 
> 
> >      set xrange [ 2.60522e+17 : 1.19840e+16 ] reverse
> nowriteback
> 
> 
> Plots generated with the following command (more code): 
> 
>   __gnuplot_plot__ data using 1:2:5:3 t 'Input
> Photometry' axes x2y1 with xyerrorbars, \
>         data using 1:4 t 'Model Photometry' axes x2y1
> with points, \
>         modelSED using 1:2 t 'Model Net (Source + Trans)
> SED' axes x2y1 with lines;
> 
> 
> 
> have BOTH wavelength and frequency increasing to the
> right (bummer!).
> [I don't know really how to show that in this context; I
> don't think I
> should attach a PostScript file to this message, so if
> anyone wants to
> see the resulting plot I can send them a copy directly.]
> 
> Is it obvious to anyone what I am doing wrong, or is it
> possible I've
> stumbled onto a bug in octave/gnuplot interaction?
> 
> Thanks in advance for your time in this matter.
> 
> - Andy
> 
> 
> -- 
> Andy Boden
>                               bode at ipac dot caltech dot edu
> Michelson Science Center/Caltech
>         http://msc.caltech.edu
> 770 S. Wilson Ave, MS 100-22             626/395-1819
> Pasadena, CA  91125                      
> 




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