Re: color map

Hi Debasish,
There are 2 ways to do it.
1) Assuming you are using gsnSpreadColors, you can set
gsnSpreadColorStart or gsnSpreadColorEnd:
http://www.ncl.ucar.edu/Document/Graphics/Resources/gsn.shtml#gsnSpreadColorEnd
http://www.ncl.ucar.edu/Document/Graphics/Resources/gsn.shtml#gsnSpreadColorStart

Using one of these resources to keep the white color around 0 in your
labelbar would require some iterating. Alternatively, you could create a
small function of your own that would calculate, based on the chosen
contour levels, what to set gsnSpreadColorStart/gsnSpreadColorEnd to.

2) Manually set the cnFillColors resource:
http://www.ncl.ucar.edu/Document/Graphics/Resources/cn.shtml#cnFillColors
using the BlWhRe colormap.

There are many application examples that show how to use cnFillColors
and the gsnSpreadColor* resources. One easy way to find them is by going
to this page:
http://www.ncl.ucar.edu/Applications/res_list.shtml
Good luck,
Adam

Debasish PaiMazumder wrote:
> Hello,
>
> I am using "BlWhRe" color map to plot difference. I always set same
> absolute value as maximum (+) and minimum (-) value of the contour to
> get all negative values in blue color and all positive values in red
> color. But when absolute values of the maximum and minimum of the
> difference are in different order, I waste lots blue or red colors.
> Is there anyway I can plot all negative values in blue color and all
> positive values in red color without setting same maximum (+) and
> minimum (-) absolute value of the contour?
>
> Thanks for your help
>
> Debasish
>
> Debasish PaiMazumder, PhD
> Hydrology & Climate Science
> Postdoctoral Researcher at UQÀM/Ouranos
> 550, Sherbrooke west, 19th floor, west tower,
> Montréal, QC, Canada H3A 1B9
> Tel: (514) 282-6464-343
> (514) 937-0042 (R)
> email: debasish_at_sca.uqam.ca <mailto:debasish_at_sca.uqam.ca>
>
>
>
>
>
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-- 
--------------------------------------------------------------
Adam Phillips			             asphilli_at_ucar.edu
National Center for Atmospheric Research   tel: (303) 497-1726
ESSL/CGD/CAS                               fax: (303) 497-1333
P.O. Box 3000				
Boulder, CO 80307-3000	  http://www.cgd.ucar.edu/cas/asphilli
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