[GRASS5] Layers Clarification

[Moritz Lennert]

Trevor Wiens wrote:
> Thanks you all for your comments.
> 
> I want to make sure I understand so I will reiterate what I
> understand you to have said.
> 
> 1. What is a vector file "layer".
> 
> In a GRASS vector file there is a single collection of spatial objects.
> Those spatial objects can be associated with one or more keys (called
> layers in current terminology). The use of these multiple keys allow
> for grouping of topologically related objects in a single layer that
> are thematically different (forests and lakes or lines and nodes). This
> also allows for linking different series of attribute data to a single
> object.

Taking the risk of confusing things a bit more, but I do want to try to 
understand. In an exchange with Radim on layers in September, we came to 
the following conclusion of the discussion:

***********
On 9/16/05, Moritz Lennert <mlennert at club.worldonline.be> wrote:
 > Ok, so it was a problem of me not understanding layers correctly.
 > Sorry...
 > Do I then understand correctly that you cannot link one layer to
 > different tables simultaneously ?

Yes, you cannot.

Radim
**************

This seems to contradict what Trevor write above, i.e. "This also allows 
for linking different series of attribute data to a single object."

So if I want to link different data tables simultaneously to the same 
object, I have to duplicate the object in two layers, or ?

The idea of layers, as I understood it so far, is to be able to have 
different objects linked to separate tables, but all in the same 
topological file.

Moritz