[GRASS-user] v.dissolve

[Jarek Jasiewicz]

Hamish wrote:
> Jarek Jasiewicz wrote:
>
>   
>> I'm trying to join all adjacentareas in vector into one (in fact all 
>> area are adjacent, and I want to convert it to one huge area)
>> I tried to use v.dissolve and I expected If I do nto specify column all 
>> borders will disolve, but it not work (I have no column with the same 
>> attribute)
>> The solution I have used is to add empty column and fill it with ther 
>> same value (both by db.execute) but it became more complicated If I have 
>> almost 200 vectors
>> Is there any more natural or more simple solution? If no please let me known
>>     
>
>
> v.dissolve (v.extract -d) is designed to dissolve common boundaries between
> areas with the same category number. So you could use v.category to remove all
> category numbers, then re-add them with only category "1" (v.category step=0)
> and then do the dissolve. If you want to get original categories back you could
> use v.distance, but there is then the question of which cat to use if different
> area cats were merged into one.
>
>
> hope that helps,
> Hamish
>
>
>
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>   
thanks
but in general it is very similar to solution I proposed - generally 
addational steps are required
t
hanks again
Jarek

btw: in v.dissolve script probably lacks g.remove at the end to remove 
temporary vector ( i.e something like dissolve_6786)