[GRASS-user] river and dams in netwok analysis

[Moritz Lennert]

Le Fri, 16 Oct 2015 18:38:28 +0200,
Etienne DELAY <etienne.delay at etu.unilim.fr> a écrit :

> Dear all,
> I'm try to understand network analysis fonction in grass 6.4. I have
> 2 layers :
> * Points layer with the spatial dams repartition
> * polylines layer with rivers
> I would like to know for each dam how is before and how is after in
> the network. I at the end I would like to export a shp files with
> those data in the attribute table.
> 
> I have find some informations here : 
> http://www.ing.unitn.it/~grass/docs/tutorial_641_en/htdocs/esercitazione/network_analysis/node1.html
> 
> And I have done that :
> 
> ##save a region
> v.in.region --overwrite --verbose output=region_central
> 
> ## clip rivers
> v.overlay --overwrite --verbose ainput=troncon_dordogne at PERMANENT 
> atype=line binput=region_central output=rivers_central operator=and
> 
> v.overlay --overwrite --verbose ainput=troncon_dordogne at PERMANENT 
> atype=line binput=bv_dordogne at PERMANENT output=rivers_bv operator=and
> v.select ainput=barrage_energie at PERMANENT
> binput=bv_dordogne at PERMANENT output=barrage_e_bv
> ##Connect dam points to the network
> ## thresh=500 means that only points within
> ## the distance of 500 metres are connected to the lines
> v.net --overwrite --verbose input=rivers_bv 
> points=barrage_e_bv at PERMANENT output=network operation=connect
> thresh=500
> 
> ## link the attribute table of the fire stations to layer 2 of the 
> network map
> v.db.connect -o --verbose map=network table=barrage_e_bv at PERMANENT
> layer=2
> 
> But I'm not so smart with data manipulation in GRASS so If someone
> can give me a hand it's nice :-)

What is your actual question, i.e. with what do you need help ?

Also note that network modules have been significantly improved in
GRASS 7, so you should consider updating to that.

Moritz