[GRASS-user] Question about layers and categories

Vincent Bain bain at toraval.fr
Fri Apr 5 03:59:10 PDT 2013

Le vendredi 05 avril 2013 à 12:37 +0200, Moritz Lennert a écrit :
> On 05/04/13 12:03, Vincent Bain wrote:
> > Hello Mortiz,
> > your reply helped me much. Removing/Reassigning layers is a matter of
> > several steps :
> > -drop previous layer definition, optionally drop related table;
> Please note: as MarkusM has already mentioned, you cannot drop a "layer 
> definition". You can drop the definition of a connection of a given 
> layer in a vector map to an attribute table. Whether or not a given 
> layer "exists" only depends on whether there are category values defined 
> for that layer for at least one feature in the map.

Ok, I was thinking "drop the layer<->table connection".

> Have you read "Vector object categories and attribute management" -> 
> "layers" on [1]. If not please do so and tell us if we can improve the 
> explanation.

I did again, it was necessary. May it be a good improvment to adjoin
some graphical material to make things faster to understand ?

> Then you should at least be able to query vector maps with several 
> layers and get a result in the command console. You do not get the 
> update dialog, though. Something to be worked on for grass7 I think.


Thank you again,

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