[GRASS5] Layers Clarification

[Trevor Wiens]

On Wed, 8 Mar 2006 09:50:28 +0100
"Radim Blazek" <radim.blazek at gmail.com> wrote:

> 
> Yes. One geometry object can be linked to more rows in attribute table.
> In that case the geometry object has more categories (the same layer)
> each pointing to one row in the attribute table. One category can only
> link to one row, no more.  The relation geometry-table can be
> one-to-many. The relation category-table can only be
> on-to-one or many-to-one.
> 
> It is probably much easier  get idea from a picture:
>    http://mpa.itc.it/radim/g51/bridge.png
> It covers all possible cases I think.
> 

Radim and others,

Thank you for taking the time to explain this. Is it possible to
manually add more than one category to a geometry object or is this
only done through automated means such as v.clean? 

Thanks. Once I get this all straight in my head I will assemble this
into a single document. Do you think my idea of having a statement on
the vector module index page with a link to a more detailed explanation
is a good idea or would somewhere else be more appropriate?

T
-- 
Trevor Wiens 
twiens at interbaun.com

The significant problems that we face cannot be solved at the same 
level of thinking we were at when we created them. 
(Albert Einstein)