[GRASS-user] Unable to get rid of duplicate polygons

[Moritz Lennert]

On 04/04/12 14:06, Paulo van Breugel wrote:
>   Ah, that is of course true. It would be nice if one had the option to
> remove the category value from the geometries when deleting the category
> value in the table (I guess there would be disadvantages too, perhaps
> the implementation).
>
> But where I got confused is that when I import a vector layer with
> overlapping polygons, I indeed get the message that "The number of
> features for those areas is stored as category in layer 2" as you
> mention below. However, when in the attribute table manager I do not see
> a second layer. Am I overlooking something or is this some bug?

AFAIK, no table is attached to layer 2. However, there are category 
values in that layer for those polygons which are the result of overlaps.

Category values are a identifiers of features that are stored within a 
vector layer. One can _optionally_ link an attribute table to that layer 
using the category values as keys.

Moritz