[GRASS-user] river and dams in netwok analysis

[Etienne DELAY]

Hi Will and Hi Moritz,
I would like to be able to export the dam layer with 2 new columns : one 
with the ID of the dam positioned before and an other one with the ID of 
the dam after in the network.

I don't know how to do that :-S

Thank you

Etienne

Cordialement

Etienne DELAY (Skype : etienne.delay.tic)
Chaire: Capital environnemental et gestion durable des cours d'eau
laboratoire GEOLAB UMR 6042 CNRS
Université de Limoges, FLSH
39E rue Camille Guérin 87036 Limoges
blog : http://elcep.legtux.org

Le 17/10/2015 08:58, Moritz Lennert a écrit :
> 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
>