[ncl-talk] Overlay on two plots

[Carl Schreck]

Is there any workaround to be able to overlay one plot onto two others?
i.e.,

a = gsn_csm_contour( wks, aData, res )
b = gsn_csm_contour( wks, bData, res )
c = gsn_csm_contour( wks, cData, res )

overlay( b, a )
overlay( c, a )

That gives the error:
fatal:NhlAddOverlay: tranform is already an annotation or overlay: 30

I tried simply copying a:
a = a2
overlay( b, a )
overlay( c, a2 )

But that gives the same error. I know it's not too difficult to call the
plotting routine twice. But a lot of times I have graphics as return values
from functions, so it'd be nice if there were some kind of copy_graphics
function so I wouldn't have to run those again.

First world problems, but figured I'd ask... Thanks!
Carl

-- 

<https://ncics.org/> *Carl J. Schreck III, PhD*
*Research Scholar*
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