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 <[email protected]> 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@PERMANENT
atype=line binput=region_central output=rivers_central operator=and
v.overlay --overwrite --verbose ainput=troncon_dordogne@PERMANENT
atype=line binput=bv_dordogne@PERMANENT output=rivers_bv operator=and
v.select ainput=barrage_energie@PERMANENT
binput=bv_dordogne@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@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@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
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