matplotlib-users

[Matplotlib-users] Highlight values outside colorbar limits

[James M. <jam...@gm...>]

Hi,

Is it possible to color values outside the colorbar limits in a different
color than the colorbar itself. So for example, an otherwise greyscale plot
could have the values outside the upperlimit in blue and those below the
lower limit in red, so that these points are not confused with the
legitimate data points (as they can be when they are just more black and
white points as default).

Thanks,
James McMurray

Re: [Matplotlib-users] Highlight values outside colorbar limits

[James M. <jam...@gm...>]

Okay, so using cm.set_over() and set_under works, but is there any way of
adding the set colors to the edges of the colorbar?

On 29 August 2011 15:47, James McMurray <jam...@gm...> wrote:

> Hi,
>
> Is it possible to color values outside the colorbar limits in a different
> color than the colorbar itself. So for example, an otherwise greyscale plot
> could have the values outside the upperlimit in blue and those below the
> lower limit in red, so that these points are not confused with the
> legitimate data points (as they can be when they are just more black and
> white points as default).
>
> Thanks,
> James McMurray
>

Re: [Matplotlib-users] Highlight values outside colorbar limits

[Benjamin R. <ben...@ou...>]

On Mon, Aug 29, 2011 at 9:59 AM, James McMurray <jam...@gm...>wrote:

> Okay, so using cm.set_over() and set_under works, but is there any way of
> adding the set colors to the edges of the colorbar?
>
>
>
This example should do what you want:

http://matplotlib.sourceforge.net/examples/api/colorbar_only.html

I hope that helps!
Ben Root

Re: [Matplotlib-users] Highlight values outside colorbar limits

[Eric F. <ef...@ha...>]

On 08/29/2011 05:44 AM, Benjamin Root wrote:
> On Mon, Aug 29, 2011 at 9:59 AM, James McMurray <jam...@gm...
> <mailto:jam...@gm...>> wrote:
>
>     Okay, so using cm.set_over() and set_under works, but is there any
>     way of adding the set colors to the edges of the colorbar?
>
>
>
> This example should do what you want:
>
> http://matplotlib.sourceforge.net/examples/api/colorbar_only.html

Also 
http://matplotlib.sourceforge.net/examples/pylab_examples/contourf_demo.html.

Note that "extend=both" is the relevant kwarg.  With contourf, the kwarg 
goes in the contourf call, and colorbar automatically gets it from the 
ContourSet. With other types of color mappable plot, the kwarg needs to 
be given directly to the colorbar call.

Eric

>
> I hope that helps!
> Ben Root
>
>
>
> ------------------------------------------------------------------------------
> EMC VNX: the world's simplest storage, starting under $10K
> The only unified storage solution that offers unified management
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>
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Re: [Matplotlib-users] Highlight values outside colorbar limits

[Benjamin R. <ben...@ou...>]

On Mon, Aug 29, 2011 at 12:30 PM, Eric Firing <ef...@ha...> wrote:

> On 08/29/2011 05:44 AM, Benjamin Root wrote:
> > On Mon, Aug 29, 2011 at 9:59 AM, James McMurray <jam...@gm...
> > <mailto:jam...@gm...>> wrote:
> >
> >     Okay, so using cm.set_over() and set_under works, but is there any
> >     way of adding the set colors to the edges of the colorbar?
> >
> >
> >
> > This example should do what you want:
> >
> > http://matplotlib.sourceforge.net/examples/api/colorbar_only.html
>
> Also
>
> http://matplotlib.sourceforge.net/examples/pylab_examples/contourf_demo.html
> .
>
> Note that "extend=both" is the relevant kwarg.  With contourf, the kwarg
> goes in the contourf call, and colorbar automatically gets it from the
> ContourSet. With other types of color mappable plot, the kwarg needs to
> be given directly to the colorbar call.
>
> Eric
>
>
Crap! Is that why my colorbars from my pcolors (or was it pcolormesh?) never
worked right?  I have been making colorbars directly for a while now because
I couldn't figure out why those colorbars didn't work right.

I think I will file a feature request to fix this inconsistency.  Probably
will be a bit involved to fix it, though.

Ben Root

Re: [Matplotlib-users] Highlight values outside colorbar limits

[Eric F. <ef...@ha...>]

On 08/29/2011 07:40 AM, Benjamin Root wrote:
>
>
> On Mon, Aug 29, 2011 at 12:30 PM, Eric Firing <ef...@ha...
> <mailto:ef...@ha...>> wrote:
>
>     On 08/29/2011 05:44 AM, Benjamin Root wrote:
>      > On Mon, Aug 29, 2011 at 9:59 AM, James McMurray
>     <jam...@gm... <mailto:jam...@gm...>
>      > <mailto:jam...@gm... <mailto:jam...@gm...>>> wrote:
>      >
>      >     Okay, so using cm.set_over() and set_under works, but is
>     there any
>      >     way of adding the set colors to the edges of the colorbar?
>      >
>      >
>      >
>      > This example should do what you want:
>      >
>      > http://matplotlib.sourceforge.net/examples/api/colorbar_only.html
>
>     Also
>     http://matplotlib.sourceforge.net/examples/pylab_examples/contourf_demo.html.
>
>     Note that "extend=both" is the relevant kwarg.  With contourf, the kwarg
>     goes in the contourf call, and colorbar automatically gets it from the
>     ContourSet. With other types of color mappable plot, the kwarg needs to
>     be given directly to the colorbar call.
>
>     Eric
>
>
> Crap! Is that why my colorbars from my pcolors (or was it pcolormesh?)
> never worked right?  I have been making colorbars directly for a while
> now because I couldn't figure out why those colorbars didn't work right.
>
> I think I will file a feature request to fix this inconsistency.
> Probably will be a bit involved to fix it, though.

It's not entirely an inconsistency.  The logic is this: extend='both' 
(or whatever) directly affects the levels used in contourf; there is 
nothing similar in imshow or pcolor*.  Adding the extend kwarg to them 
would simply be putting it in place for later use by colorbar.

Eric

>
> Ben Root
>
>
>
> ------------------------------------------------------------------------------
> EMC VNX: the world's simplest storage, starting under $10K
> The only unified storage solution that offers unified management
> Up to 160% more powerful than alternatives and 25% more efficient.
> Guaranteed. http://p.sf.net/sfu/emc-vnx-dev2dev
>
>
>
> _______________________________________________
> Matplotlib-users mailing list
> Mat...@li...
> https://lists.sourceforge.net/lists/listinfo/matplotlib-users