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

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

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.
In principle you could also manually re-map the palette definition using
   set palette functions  R(gray), G(gray), B(gray)
[but I have not actually tested this]

	Ethan