quickly return colorbar ticks?

Community matplotlib-users
1

Dear all matplotlib users,

I found there is not a get_ticks method available for colorbar instance,
how could I quick get the ticks of a colorbar?

thanks,

Chao

···

–

Chao YUE
Laboratoire des Sciences du Climat et de l’Environnement (LSCE-IPSL)
UMR 1572 CEA-CNRS-UVSQ
Batiment 712 - Pe 119
91191 GIF Sur YVETTE Cedex

Tel: (33) 01 69 08 29 02; Fax:01.69.08.77.16

2

This is a constant source of confusion. The colorbar object should be thought of as just another subaxes. To get the ticks, you want the ticks from the colorbar’s yaxis or xaxis object accordingly. Of course, I could have sworn we added a helper function for this at some point, but I could be wrong.

I hope that helps!
Ben Root

···

On Tue, Jul 2, 2013 at 5:43 AM, Chao YUE <chaoyuejoy@…287…> wrote:

Chao YUE
Laboratoire des Sciences du Climat et de l’Environnement (LSCE-IPSL)
UMR 1572 CEA-CNRS-UVSQ
Batiment 712 - Pe 119
91191 GIF Sur YVETTE Cedex

Tel: (33) 01 69 08 29 02; Fax:01.69.08.77.16

Dear all matplotlib users,

I found there is not a get_ticks method available for colorbar instance,
how could I quick get the ticks of a colorbar?

thanks,

Chao

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3

Thanks Ben. I tried but still confused.

In [8]: fig,ax = plt.subplots()

In [9]: ax.plot(range(100))
Out[9]: [<matplotlib.lines.Line2D at 0x4cadb50>]

In [10]: ax.get_xticks()
Out[10]: array([ 0., 20., 40., 60., 80., 100.])

In [11]: ax.get_yticks()
Out[11]: array([ 0., 20., 40., 60., 80., 100.])

In [12]: draw()

In [13]: cs = ax.imshow(np.arange(100).reshape(10,10))

In [14]: draw()

In [15]: cbar = plt.colorbar(cs,ticks=np.arange(0,100,10))

In [16]: cbar.ax.get_yticks()
Out[16]:
array([ 0. , 0.1010101 , 0.2020202 , 0.3030303 , 0.4040404 ,
0.50505051, 0.60606061, 0.70707071, 0.80808081, 0.90909091])

there are many methods avaialbe for cbar.ax.yaxis object:
In [19]: cbar.ax.yaxis.gettick?
cbar.ax.yaxis.get_major_ticks
cbar.ax.yaxis.get_majorticklabels
cbar.ax.yaxis.get_majorticklines
cbar.ax.yaxis.get_majorticklocs
cbar.ax.yaxis.get_minor_ticks
cbar.ax.yaxis.get_minorticklabels
cbar.ax.yaxis.get_minorticklines
cbar.ax.yaxis.get_minorticklocs
cbar.ax.yaxis.get_ticklabel_extents
cbar.ax.yaxis.get_ticklabels
cbar.ax.yaxis.get_ticklines
cbar.ax.yaxis.get_ticklocs
cbar.ax.yaxis.get_ticks_position

I tried
In [20]: cbar.ax.yaxis.get_majorticklocs()
Out[20]:
array([ 0. , 0.1010101 , 0.2020202 , 0.3030303 , 0.4040404 ,
0.50505051, 0.60606061, 0.70707071, 0.80808081, 0.90909091])

But it doesn’t give the tick locs as the normal axes?

could you explain a bit further?

thanks et cheers,

Chao

···

On Tue, Jul 2, 2013 at 5:43 AM, Chao YUE <[hidden email]> wrote:

Chao YUE
Laboratoire des Sciences du Climat et de l’Environnement (LSCE-IPSL)
UMR 1572 CEA-CNRS-UVSQ
Batiment 712 - Pe 119
91191 GIF Sur YVETTE Cedex

Tel: (33) 01 69 08 29 02; Fax:01.69.08.77.16

Dear all matplotlib users,

I found there is not a get_ticks method available for colorbar instance,

how could I quick get the ticks of a colorbar?

thanks,

Chao

This SF.net email is sponsored by Windows:

Build for Windows Store.

http://p.sf.net/sfu/windows-dev2dev

Matplotlib-users mailing list

[hidden email]

https://lists.sourceforge.net/lists/listinfo/matplotlib-users

4

Remember, there is a difference between a tick location, and a tick label.
A colormap works from 0 to 1, so that is its data coordinates. We merely
label the ticks with the appropriate values. Try
cbar.ax.yaxis.get_ticklabels().

Cheers!
Ben Root

···

On Wed, Jul 3, 2013 at 3:13 AM, ChaoYue <chaoyuejoy@...287...> wrote:

Thanks Ben. I tried but still confused.

In [8]: fig,ax = plt.subplots()

In [9]: ax.plot(range(100))
Out[9]: [<matplotlib.lines.Line2D at 0x4cadb50>]

In [10]: ax.get_xticks()
Out[10]: array([ 0., 20., 40., 60., 80., 100.])

In [11]: ax.get_yticks()
Out[11]: array([ 0., 20., 40., 60., 80., 100.])

In [12]: draw()

In [13]: cs = ax.imshow(np.arange(100).reshape(10,10))

In [14]: draw()

In [15]: cbar = plt.colorbar(cs,ticks=np.arange(0,100,10))

In [16]: cbar.ax.get_yticks()
Out[16]:
array([ 0. , 0.1010101 , 0.2020202 , 0.3030303 , 0.4040404 ,
        0.50505051, 0.60606061, 0.70707071, 0.80808081, 0.90909091])

there are many methods avaialbe for cbar.ax.yaxis object:
In [19]: cbar.ax.yaxis.get*tick*?
cbar.ax.yaxis.get_major_ticks
cbar.ax.yaxis.get_majorticklabels
cbar.ax.yaxis.get_majorticklines
cbar.ax.yaxis.get_majorticklocs
cbar.ax.yaxis.get_minor_ticks
cbar.ax.yaxis.get_minorticklabels
cbar.ax.yaxis.get_minorticklines
cbar.ax.yaxis.get_minorticklocs
cbar.ax.yaxis.get_ticklabel_extents
cbar.ax.yaxis.get_ticklabels
cbar.ax.yaxis.get_ticklines
cbar.ax.yaxis.get_ticklocs
cbar.ax.yaxis.get_ticks_position

I tried
In [20]: cbar.ax.yaxis.get_majorticklocs()
Out[20]:
array([ 0. , 0.1010101 , 0.2020202 , 0.3030303 , 0.4040404 ,
        0.50505051, 0.60606061, 0.70707071, 0.80808081, 0.90909091])

But it doesn't give the tick locs as the normal axes?

could you explain a bit further?

thanks et cheers,

Chao