[GRASS-user] change centroids/area categories by step values (was: areas, isles and centroids - topology doubts about category assignment)

[G. Allegri]

It works... I'm sorry, it was a problem with my vector. It gave me
errors because it wasn't correctly dissolved...
Thanks anyway, for the hint.

I will open another post for the other question:
why is the creation of new vectors in v.categories, v.dissolve, and
similar commands needed? Couldn't it be an option, so one could
overwrite the original vector? I imagine it shouldn't be difficult to
realize it...

2008/8/9 Moritz Lennert <mlennert at club.worldonline.be>:
> On 08/08/08 19:43, G. Allegri wrote:
>>
>> I simplify the questions of the previous post:
>>
>> I have dissolved completely a polygonal layer [fig.1] producing the
>> one in fig.2, which is composed of 21 areas, 21 isles (the same
>> features of "areas"), and 11 centroids attached to the "true" areas.
>> The 11 centroids has the same category value (=1). Now I need to
>> differentiate the 11 areas, so I would need to give the centroids
>> unique, different, values.
>> I've tried all the combinations with v.edit, v.category, etc.,
>> deleting and re-adding categories, but nothing seems to do what I
>> need.
>
> Could you be more specific about what exactly you tried, what happended and
> why this does fit your needs ?
>
> Normally
>
> v.category in= out= option=del
> v.category in= out= option=add
>
> Should do the trick...
>
>
>
>> I'm sure it's a stupid task but, how to do it?
>>
>> fig.1 www.geospatial.it/allegri/not_dissolved.ong
>> fig.2 www.geospatial.it/allegri/dissolved.ong
>
> I get 404 Not Found...
>
> Moritz
>