[GRASS-dev] RGB colored and Transparent areas in one vector map

[Moritz Lennert]

On 06/03/17 12:44, Nikos Alexandris wrote:
> Dear all,
>
> I have an rgb_column with RGBs for a vector map. For some areas, I would
> like to have no color, as in trasparent.
>
> If I am not wrong, we can't do that, ie define "nv" as we can do in
> color rules for a raster map.
>
> Can we?

I don't think so,

The easiest workaround I see is to set your rgb_colum to NULL where you 
want transparency (or to create a separate transparency column) and 
display your map twice:

d.vect MyMap rgb_column=MyCol where="MyCol IS NOT NULL"
or
d.vect MyMap rgb_column=MyCol where="transparency = 0"

+

d.vect MyMap fcol=none where="MyCol IS NULL"
or
d.vect MyMap fcol=none where="transparency = 1"

Moritz