Re: [Gnuplot-info] log color bar: out of range data --> invisible

[Ethan A M. <eam...@gm...>]

On Friday, 03 April 2015 03:04:32 PM Ethan A Merritt wrote:
> On Friday, 03 April 2015 09:49:48 PM theozh wrote:
> > OK, thanks John and Ethan. This trick works.
> > 
> > plot "Matrix2.dat" matrix using 1:2:($3<0 ? NaN : $3) with image
> > 
> > > 
> > > "set logscale cb" has been buggy/inconsistent for a long time.
> > > Some fixes went into the code recently, but I am not convinced
> > > that it is working consistently even now.   I suggest that if
> > > possible you re-work your plot so that it does not require
> > > log-scaling on the colorbar.
> > > 
> > Good to know that "set logscale cb" is obviously still buggy...
> > 
> > I do not have a choice. I want to diplay currents which are ranging e.g.
> > from 1e-11 to 1e-6. How should I display this without logscale?
> 
> There's no problem with log-scaling the value being plotted,
> the issue is with the settings for the color bar itself.
> So...
> 
>    unset log cb
>    set cbrange [*:*] noextend
>    plot $DATA matrix using 1:2:(log($3)) with image
> 
> Of course this is a different mapping of z value -> color than before.

Actually, I now see it's the same mapping.  I had not realized that.
Bug?  Feature?


FWIW I found the specific bug that fails to color negative
values as NaN (background) when the cb axis is in log mode.
So that will be fixed in the next patchlevel release of version 5.


	Ethan