[GRASS-user] R: [GRASS-dev] Problems in adding tables to a map

[Moritz Lennert]

On 22/11/12 16:59, Aldo Clerici wrote:
>
> So, if I need to assign different attributes to the objects in the vector
> file I need to assign new categories to the objects and store them in a new
> layer to be connected to a different table.
> But how can I add a new layer to a vector?
> v.category seems to produce a new vector map with new category values but
> doesn't add a new layer in the input map.

Sure it does. v.category op=add layer=2 ... will create a new map with 
the old category values preserved in layer 1 and with new category 
values in layer 2. And as mentioned in a previous mail, in GRASS7 you 
can simply copy the category values of layer 1 to layer 2 with op=transfer.

> But I suppose there is another simpler way to add and fill a new layer as,
> for example, to reclass the category numbers of a map and put the reclassed
> categories in a new layer to be connected to a new table with new
> attributes. Or not?

AFAIK, v.reclass does not allow you to chose the layer of categories in 
the new map, only which layer to use in the old map.

Moritz