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!<br>
<br>
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.<br><br><div><span class="gmail_quote">On 6/19/06, <b class="gmail_sendername">Hamish</b> <<a href="mailto:hamish_nospam@yahoo.com">hamish_nospam@yahoo.com</a>> wrote:</span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
M S wrote:<br>> so you have layers that can be linked to various tables. if one does<br>> a v.patch command and now has two "layers" of lines, how can they both<br>> be put on the same layer, or does that not even matter? i guess its
<br>> like if you have a polygon coverage in workstation. then u can build<br>> it for lines (the .aat) and polygons (the .pat). then u can add<br>> attributes and manipulate them for the different attribute tables.
<br>> however, since u cant have various "layers" of the same datatype in a<br>> coverage, i think that is where i get confused.<br><br><br><br>if you have two vectors with dissimilar tables, v.patch won't/can't do
<br>it.<br><br>The "-e" flag was recently added to v.patch to try.<br><br>see also the v.append script on the GRASS Wiki Add-ons page:<br> <a href="http://grass.gdf-hannover.de/wiki/GRASS_AddOns#Vector_add-ons">
http://grass.gdf-hannover.de/wiki/GRASS_AddOns#Vector_add-ons</a><br><br>v.append was written before the v.patch "-e" flag.<br><br><br>There's an example of a module which will result in 2 layer output, but<br>I can't remember what it is right now.
<br><br><br>Hamish<br></blockquote></div><br>