Re: [Matplotlib-users] how to reverse the colorbar and its label at the same time?

[Chao Y. <cha...@gm...>]

Thanks, I think cbar.ax.invert_yaxis() is what I am looking for.

Chao

On Sat, Nov 10, 2012 at 4:51 PM, Damon McDougall
<dam...@gm...>wrote:

> On Sat, Nov 10, 2012 at 9:41 AM, Paul Hobson <pmh...@gm...> wrote:
> > On Sat, Nov 10, 2012 at 7:07 AM, Chao YUE <cha...@gm...> wrote:
> >>
> >> Dear all,
> >>
> >> Is there a way to reverse the colorbar label, the default is small
> value at the bottom and big value at the top, yet I would like the big
> value at the bottom and small value at the top.
> >>
> >> all code in pylab mode.
> >>
> >> import numpy as np
> >> import matplotlib as mat
> >>
> >> a = np.arange(100).reshape(10,10)
> >> contourf(a,levels=np.arange(0,101,10))
> >> colorbar()
> >>
> >> in the above figure, colorbar label shows 0 at the bottom and 100 at
> the top.
> >> Yet I want the 0 at the top and the 100 at the bottom, with the same
> sequence of colors in the colorbar.
> >>
> >> One way is to reverse the cmap, and then reverse the colorbar labels at
> the same time:
> >> a = np.arange(100).reshape(10,10)
> >> contourf(a,levels=np.arange(0,101,10),cmap=mat.cm.jet_r)
> >> cbar = colorbar()
> >> cbar.set_ticks(np.arange(0,101,10))
> >> cbar.set_ticklabels(np.arange(100,-1,-10))
> >
> > Chao,
> >
> > I think it's as simple as:
> >
> > import numpy as np
> > import matplotlib.pyplot as plt
> >
> > a = np.arange(100).reshape(10,10)
> > fig, ax1 = plt.subplots()
> > CS = ax1.contourf(a,levels=np.arange(0,101,10))
> > cbar = plt.colorbar(CS)
> > cbar.ax.invert_yaxis()
> >
> > Does that produce the desired results?
> > -p
>
> Or, you could plot -a instead of a.
>
> --
> Damon McDougall
> http://www.damon-is-a-geek.com
> Institute for Computational Engineering Sciences
> 201 E. 24th St.
> Stop C0200
> The University of Texas at Austin
> Austin, TX 78712-1229
>



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Chao YUE
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