[GRASS-user] v.dissolve

[Hamish]

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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