[ncl-talk] Contour plot fill error with low values

[Guido Cioni]

Dear all,
I've been struggling with this problem for a while now, and that led me to believe that I may have discovered a bug or at least an unexpected behaviour.

Little bit of background. I process NWP model output daily for my website and among the multiple plots that I do with NCL there is one that uses mid- low-level clouds, precip. and snow on the same map. Now, what happens sometimes is that values of either rain or snow are really small or even 0. Although I have fixed explicit levels, this causes the plotting routine to produce the warning 

warning:ContourPlotSetValues: Data values out of range of levels set by EXPLICITLEVELS mode

and fill the entire contour area with a single color, as you can see in the animation that I'm attaching. This basically covers everything on the plot, making any interpretation of the results impossible. I think that, even in the case of low values, the entire area should stay transparent...


Is there any way to fix this?

I'm attaching an example script. 

Cheers 

Guido Cioni
http://guidocioni.altervista <http://guidocioni.altervista/>.org

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