Hi all,
I am having a problem with manipulating colorbars. I want to take the cm.Blues colorbar and edit it so that the lowest end of the colorbar is light blue instead of white, or in other words I want to remove the lightest 1/4 of the colorbar and just keep the darker end.
Is there any easy way to do this?
Any help would be greatly appreciated!
Thanks
Ian Harry
Ian,
First, as a point of semantics, you are talking about colormaps, not colorbars.
I have attempted at one point a framework to allow users to manipulate colormaps, but it is very difficult to make it work in a generalized framework. However, it is “relatively” easier to specifically hack a particular colormap to get the results you need.
import matplotlib.cm as cm
import matplotlib.colors as mcolors
cm.Blues._init() # forces it to internally create the ‘_lut’ array
newBlues = mcolors.LinearSegmentedColormap.from_list(“newBlues”, cm.Blues._lut[cm.Blues.N/3:-3, :-1], 256)
This should create a new colormap by reinterpolating the last 2/3rds of the Blues colordata to a new 256 colors colormap.
I hope this helps!
Ben Root
On Thu, Dec 9, 2010 at 9:01 AM, Ian Harry <ian.harry@…3362…> wrote:
Hi all,
I am having a problem with manipulating colorbars. I want to take the cm.Blues colorbar and edit it so that the lowest end of the colorbar is light blue instead of white, or in other words I want to remove the lightest 1/4 of the colorbar and just keep the darker end.
Is there any easy way to do this?
Any help would be greatly appreciated!
Thanks
Ian Harry
Hi Ben,
Thanks for the suggestion, unfortunately I get:
Traceback (most recent call last):
File “spin_bank.py”, line 43, in ?
newBlues = mcolors.LinearSegmentedColormap.from_list(“newBlues”, cm.Blues._lut[cm.Blues.N/3:-3, :-1], 256)
AttributeError: class LinearSegmentedColormap has no attribute ‘from_list’
Am I missing something?
Thanks
Ian
On 10 December 2010 15:50, Benjamin Root <ben.root@…1304…> wrote:
On Thu, Dec 9, 2010 at 9:01 AM, Ian Harry <ian.harry@…1663…> wrote:
Hi all,
I am having a problem with manipulating colorbars. I want to take the cm.Blues colorbar and edit it so that the lowest end of the colorbar is light blue instead of white, or in other words I want to remove the lightest 1/4 of the colorbar and just keep the darker end.
Is there any easy way to do this?
Any help would be greatly appreciated!
Thanks
Ian Harry
Ian,
First, as a point of semantics, you are talking about colormaps, not colorbars.
I have attempted at one point a framework to allow users to manipulate colormaps, but it is very difficult to make it work in a generalized framework. However, it is “relatively” easier to specifically hack a particular colormap to get the results you need.
import matplotlib.cm as cm
import matplotlib.colors as mcolorscm.Blues._init() # forces it to internally create the ‘_lut’ array
newBlues = mcolors.LinearSegmentedColormap.from_list(“newBlues”, cm.Blues._lut[cm.Blues.N/3:-3, :-1], 256)This should create a new colormap by reinterpolating the last 2/3rds of the Blues colordata to a new 256 colors colormap.
I hope this helps!
Ben Root
Ian Harry
School of Physics & Astronomy
Queens Buildings, The Parade
Cardiff, CF24 3AA
What version of matplotlib are you using?
Ben Root
On Fri, Dec 10, 2010 at 11:00 AM, Ian Harry <ian.harry@…3363…> wrote:
Hi Ben,
Thanks for the suggestion, unfortunately I get:
Traceback (most recent call last):
File “spin_bank.py”, line 43, in ?newBlues = mcolors.LinearSegmentedColormap.from_list("newBlues", cm.Blues._lut[cm.Blues.N/3:-3, :-1], 256)
AttributeError: class LinearSegmentedColormap has no attribute ‘from_list’
Am I missing something?
Thanks
Ian
On 10 December 2010 15:50, Benjamin Root <ben.root@…1304…> wrote:
On Thu, Dec 9, 2010 at 9:01 AM, Ian Harry <ian.harry@…83…1663…> wrote:
Hi all,
I am having a problem with manipulating colorbars. I want to take the cm.Blues colorbar and edit it so that the lowest end of the colorbar is light blue instead of white, or in other words I want to remove the lightest 1/4 of the colorbar and just keep the darker end.
Is there any easy way to do this?
Any help would be greatly appreciated!
Thanks
Ian Harry
Ian,
First, as a point of semantics, you are talking about colormaps, not colorbars.
I have attempted at one point a framework to allow users to manipulate colormaps, but it is very difficult to make it work in a generalized framework. However, it is “relatively” easier to specifically hack a particular colormap to get the results you need.
import matplotlib.cm as cm
import matplotlib.colors as mcolorscm.Blues._init() # forces it to internally create the ‘_lut’ array
newBlues = mcolors.LinearSegmentedColormap.from_list(“newBlues”, cm.Blues._lut[cm.Blues.N/3:-3, :-1], 256)This should create a new colormap by reinterpolating the last 2/3rds of the Blues colordata to a new 256 colors colormap.
I hope this helps!
Ben Root