[GRASS-user] How to link or combine adjacent vector lines

[Moritz Lennert]

On 13/02/12 12:06, Hamish wrote:
> Moritz wrote:
>> With options first and multi v.build.polylines just copies
>> the attribute tables as is, i.e. it does not delete any
>> lines for which there are no more category values in the
>> vector file.
>>
>> To create an attribute table that corresponds to the current
>> vector amp with the following steps (supposing that the
>> vector map is called river_poly):
>>
>> db.copy from_table=river_poly to_table=river_bak # create
>> backup of existing table
>> v.db.connect -d river_poly # erase line between vector map
>> and table river_poly
>> db.droptable river_poly # erase table river_poly
>> v.db.addtable river_poly # create new table for vector map
>> river_poly
>>
>> If you do all this using an SQL backend (e.g. SQLite or
>> PostgreSQL), you can then use v.db.join to join any
>> attributes from the original table river_bak to the new
>> table river_poly.
>
>
> would 'v.extract list=1-9999999' also work?

Yep, and it's a bit shorter than my solution while keeping all the 
original attributes without having to go through v.db.join ... ;-)

Moritz