[GRASS-dev] Streams extraction from streams map

[Markus Neteler]

On Tue, May 01, 2007 at 12:37:15PM +0200, Markus Neteler wrote:
> Hi,
> 
> I have a network of streams (say, Spearfish or better the new
> NC data set at http://mpa.itc.it/grasstutor/data_menu3rd.phtml )
> and want to extract a single stream system. Names are lacking,
> is there any trick to extract topologically connected lines
> into a new map?

Probably we need some equivalent to the "sides" operator in
v.to.db (which tells you the cats of the left and right polygon).
Some magic which finds the lines which are connected and writes
out some related attribute(s).

Ideas welcome,
Markus