I am trying to plot a variable that is in a NetCDF file using GrADS and I would like to plot only the values that are smaller than -20 (could be any other number as an example). I can't find a way to do it though. I saw several examples of variable substitution using both maskout
and const
(for example define ones = const(const(maskout(p,p-10),1),0,-u)
, which is here) but I couldn't make that work for my purposes.
I want the variable at a given point not plotted in case its value is below -20, and not this value change to another one in such point.