more questions on layers (perhaps overflowing into v.patch)...<br>
<br>
i did a v.patch of some points, street lines, and lines that connect
the points to streets. then i did the v.clean to snap and break
the new node points.<br>
<br>
when i query by mouse on the display, the streets from the v.patch output, i get somethings i dont understand:<br>
<br>
1) it doesnt seem that v.clean is doing any snapping or breaking.
i click on a street line (in the v.patch output file) and it shows one
line where the other line feature was patched in to connect to the
streets. i would have expected a node and a break in the line to
occur? i used v.clean with the point and line features and a
threshhold of .1.<br>
<br>
2) in the v.patch output, when i click on the street lines, it comes up
in the FORM box (under the map, mapset, feature type, length) Layer: 1,
category: 75, Database connection not defined. at this point i
intentionally dont have any database connections
defined, as i'm just trying to get a simple geometric network to run
through v.net.steiner.<br>
<br>
3) in the v.patch output, when i click on the lines connecting the
points to the streets, there is no information in the FORM that comes
up. I do get the map, mapset, feature type, length). in
QGIS this shows as line feature, layer 0. the streets show as
line feature, layer 1.<br><br>
any reason why after v.patch i get the lines on different layers?<br>
<br>
<br><div><span class="gmail_quote">On 6/19/06, <b class="gmail_sendername">M S</b> <<a href="mailto:mseibel@gmail.com">mseibel@gmail.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;">
<div>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.</div><div><span class="e" id="q_10bebad3710e9b70_1"><br><br><div><span class="gmail_quote">On 6/19/06, <b class="gmail_sendername">Hamish</b> <<a href="mailto:hamish_nospam@yahoo.com" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">
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" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">
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>
</span></div></blockquote></div><br>