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Re: colorbar to display the 0 in the middle [message #47487 is a reply to message #47399]

Fri, 10 February 2006 03:12

David Fanning
Messages: 11724
Registered: August 2001

Senior Member

Vigeesh Nambiar writes:

> But, I want something like this
> minval = -30
> maxval = +50
>
> i.e my colorbar should look something like this
> ______ 50
> | |
> | |
> | |
> | |
> | |
> | |
> | |- 0
> | |
> | |
> | |
> | |
> | |
> | |
> ------- -30
>
> :-)
>
> Basically, what I want is that the color for the data value 0 should be
> the same for all the output images. That is, if I use a Blue-Red color
> table, then the 0 data value should always be green. The main problem
> is because the minimum and maximum value keeps on changing for
> different arrays. If for the first array the min value is -30 and max
> is 50, for the second array it might be -50 and +75, and so on.

Are you SURE that is what you want? Differential scaling on the positive
and negative sides of your data, and differential scaling on all data
sets!? Wouldn't you want to *compare* the data at some point?

I don't know. It's your data analysis. But this is simply a mapping
problem. Scale negative values into 100 values. Scale positive values
into 100 values. Use a color table that has 200 values. Label it with
YTICKV (since the scale is no longer linear). Just don't include my
name in the acknowledgements, please. :-)

Cheers,

David

--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.dfanning.com/

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[Message index]

		colorbar to display the 0 in the middle By: vigeesh on Thu, 09 February 2006 17:53
		Re: colorbar to display the 0 in the middle By: vigeesh on Sat, 11 February 2006 22:54
		Re: colorbar to display the 0 in the middle By: David Fanning on Sun, 12 February 2006 07:57
		Re: colorbar to display the 0 in the middle By: savoie on Fri, 10 February 2006 08:11
		Re: colorbar to display the 0 in the middle By: David Fanning on Fri, 10 February 2006 07:59
		Re: colorbar to display the 0 in the middle By: vigeesh on Fri, 10 February 2006 07:25
		Re: colorbar to display the 0 in the middle By: vigeesh on Fri, 10 February 2006 07:22
		Re: colorbar to display the 0 in the middle By: ph le sager on Fri, 10 February 2006 03:48
		Re: colorbar to display the 0 in the middle By: David Fanning on Fri, 10 February 2006 03:12
		RE: colorbar to display the 0 in the middle By: David Fanning on Sun, 30 September 2012 16:47
		RE: colorbar to display the 0 in the middle By: larsonej on Sun, 30 September 2012 16:22

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