Hi Markus,<br>Thank you for your reply.<br><br>This is the original vector:<br><br>v.db.connect -p cont<br>Vector map <cont@PERMANENT> is connected by:<br>layer <1> table <cont> in database </home/stuart/grassdata/aawt_mga55/PERMANENT/dbf/> through driver <dbf> with key <cat><br>
<br><br>The v.split command and output:<br><br>v.split input=cont output=contSplit length=10000<br><br> 100%<br>Building topology for vector map <contSplit>...<br>Registering primitives...<br>37377 primitives registered<br>
2176557 vertices registered<br>Building areas...<br> 100%<br>0 areas built<br>0 isles built<br>Attaching islands...<br>Attaching centroids...<br> 100%<br>Number of nodes: 38377<br>Number of primitives: 37377<br>Number of points: 0<br>
Number of lines: 37377<br>Number of boundaries: 0<br>Number of centroids: 0<br>Number of areas: 0<br>Number of isles: 0<br><br><br>Proof that there is no attribute table:<br><br>v.db.connect -g contSplit<br>ERROR: Database connection for map <contSplit@PERMANENT> is not defined in DB file<br>
<br><br>I hope that this is this what you were after.<br><br>Thanks,<br>Stuart<br><br><br><br><br><br><br><br><br><br><div class="gmail_quote">On Tue, Aug 24, 2010 at 5:22 PM, Markus Metz <span dir="ltr"><<a href="mailto:markus.metz.giswork@googlemail.com">markus.metz.giswork@googlemail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;"><div class="im">Stuart Gralton wrote:<br>
> Hello Everyone,<br>
><br>
> I am trying to use v.overlay to clip contour lines for a specific area. The<br>
> contour lines were imported into GRASS from a shapefile which is about 33Mb.<br>
> The query was as follows:<br>
><br>
> v.overlay ainput=contour atype=line binput=boundingbox output=contour_clip<br>
> operator=and<br>
><br>
> The operation took 16 hours to complete, which seems excessive. Is there<br>
> anything that I can do to speed things up?<br>
><br>
> I am aware of v.split, v.select, v.clean as suggestions from other posts as<br>
> ways of increasing performance. Unfortunately none of these helped me very<br>
> much:<br>
><br>
> v.split seems to drop the attribute table (but it has amazing effects on<br>
> performance).<br>
<br>
</div>v.spllt does copy all attribute tables. Can you post the output of<br>
v.db.connect -p or v.db.connect -g for the original vector and the<br>
output of v.split?<br>
<br>
Markus M<br>
<div class="im"><br>
> v.select helps a little, but due to the nature of the data, not many<br>
> features are removed.<br>
> v.clean did not have any effect. The data is from the government, and is<br>
> already of high quality.<br>
><br>
><br>
> Is there anything that I am missing? Or is there any way to preserve the<br>
> attribute table when using v.split?<br>
><br>
> Thanks in advance,<br>
> Stuart<br>
><br>
><br>
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</div></div></blockquote></div><br>