[GRASS-user] [GRASSLIST:1119] Re: layers in vector datasets

[M S]

after i work through this problem and understand whats going on, i would
love to add to the wiki page for arc users.  its grinding out the function
now for v.net.steiner, with a county wide dataset for streets, and 208
steiner points its got some computing to do!  Go GRASS & Linux!

can anyone explain why one would want or use arcs on different layers in the
same grass vector dataset?  i cant think of how this would be used.

On 6/19/06, Hamish <hamish_nospam at yahoo.com> wrote:
>
> M S wrote:
> > so you have layers that can be linked to various tables.  if one does
> > a v.patch command and now has two "layers" of lines, how can they both
> > be put on the same layer, or does that not even matter?  i guess its
> > like if you have a polygon coverage in workstation.  then u can build
> > it for lines (the .aat) and polygons (the .pat).  then u can add
> > attributes and manipulate them for the different attribute tables.
> > however, since u cant have various "layers" of the same datatype in a
> > coverage, i think that is where i get confused.
>
>
>
> if you have two vectors with dissimilar tables, v.patch won't/can't do
> it.
>
> The "-e" flag was recently added to v.patch to try.
>
> see also the v.append script on the GRASS Wiki Add-ons page:
>   http://grass.gdf-hannover.de/wiki/GRASS_AddOns#Vector_add-ons
>
> v.append was written before the v.patch "-e" flag.
>
>
> There's an example of a module which will result in 2 layer output, but
> I can't remember what it is right now.
>
>
> Hamish
>
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