[GRASS-user] Snap across layers

[ivan marchesini]

Hi Martin and Luca...
I have just tried with v.out.ascii as you suggested...

I have two test vector layer ("pippo" and "pippo1")
each one contains only one area (without centroid)
they are really similar and vertex are quite near each other (~30
meters)

I have tried these commands:

v.edit a3 tool=create
v.out.ascii pippo1 format=standard | v.edit a3 tool=add bgmap=pippo
thre=200 snap=vertex

it works but, at the end I obtain only a copy of the first map (i.e.
"a3" is exactly equal to "pippo1")
It seems that only "add" works... but not the snap and the threshold...

any suggestion?

many thanks

Ivan






Il giorno mar, 29/01/2008 alle 15.52 +0100, Martin Landa ha scritto:
> Hi,
> 
> 2008/1/28, Luca Casagrande <luca.casagrande at gmail.com>:
> > Markus Neteler ha scritto:
> > > - v.edit does it:
> > >       bgmap   Name of background vector map(s) snap to
> > > - the new digitizer in wxgrass does it (not yet enabled by default)
> 
> Luca:
> > Before moving to my data, I am doing some tests with 2 vector layers:
> >
> > http://img337.imageshack.us/my.php?image=schermatamapdisplay1vp5.png
> >
> > Basically the small one, should snap to the bigger one.
> > The command line I use is this:
> >
> > v.edit map=origine bgmap=destinazione cat=1-999 tool=snap thresh=-1
> >
> > But nothing change.
> >
> > In the log I have got a lot of line like this, both if i set thresh -1
> > or 500
> > [..]
> > D1/1: Vect_set_thresh(): thresh = 0.000000
> > [..]
> >
> 
> tool 'snap' in v.edit uses library fn Vect_snap_lines() which doesn't
> support snapping to the vector features from background map layer.
> 
> Snapping mode (no, node, vertex) and background map option works
> currently only for tool='add'. For now, try to create an empty vector
> map, export to ascii format the map you want to modify and update the
> empty map, e.g.
> 
> v.edit a3 tool=create
> v.out.ascii a2 format=standard | v.edit a3 tool=add bgmap=a1 id=1-999
> thre=500 snap=node
> 
> Martin
> 
-- 
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Preferisco formati liberi.
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Ivan Marchesini
Department of Civil and Environmental Engineering
University of Perugia
Via G. Duranti 93/a 
06125
Perugia (Italy)
Socio fondatore GFOSS "Geospatial Free and Open Source Software" http://www.gfoss.it
e-mail: marchesini at unipg.it
        ivan.marchesini at gmail.com
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