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Re: Adding extra white in middle of colour bar [message #85606 is a reply to message #85604]

Wed, 21 August 2013 06:03

David Fanning
Messages: 11724
Registered: August 2001

Senior Member

ljs15@fsmail.net writes:

> I am plotting data that range from negative to positive, so am using a blue-white-red colour bar. However, I would like there to be more white in the middle of the bar.
>
> At the moment I'm using the following clumsy commands to achieve this:
>
> maxv = 10
> cgloadct, 13, /brewer, /reverse, ncolors=9, bottom=0, /silent, clip=[0,225]
> cgloadct, 16, /brewer, ncolors=9, bottom=12, /silent, clip=[0,225]
> clev = scale_vector(findgen(21), -maxv, maxv)
> ccol = bindgen(21)
> ;Make middle levels white
> ccol[9:11] = cgcolor('white')
>
> and then:
>
> cgColorbar, ncolors=20, range=[-maxv, maxv]
>
> While this gives me the plot shading I want, the colour bar is incorrect. As I have manually altered the middle values to white, they don't show in the colour bar, which only uses the 18 colours defined by cgloadct.
>
> Is there a simple way around this?

I think the simplest way around it is this:

cgLoadCT, 22, /Brewer, /Reverse, NColors=20
cgColorBar, NColors=20, range=[-10,10]

Cheers,

David

--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.idlcoyote.com/
Sepore ma de ni thue. ("Perhaps thou speakest truth.")

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[Message index]

		Adding extra white in middle of colour bar By: Sir Loin Steak on Wed, 21 August 2013 03:20
		Re: Adding extra white in middle of colour bar By: David Fanning on Wed, 21 August 2013 06:03
		Re: Adding extra white in middle of colour bar By: Sir Loin Steak on Wed, 21 August 2013 06:33
		Re: Adding extra white in middle of colour bar By: David Fanning on Wed, 21 August 2013 07:04
		Re: Adding extra white in middle of colour bar By: Sir Loin Steak on Wed, 21 August 2013 12:52
		Re: Adding extra white in middle of colour bar By: David Fanning on Wed, 21 August 2013 17:13
		Re: Adding extra white in middle of colour bar By: Sir Loin Steak on Thu, 22 August 2013 05:57
		Re: Adding extra white in middle of colour bar By: David Fanning on Thu, 22 August 2013 06:15

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