<p dir="ltr">Hi,<br>
The Qgis dissolve is very slow. I tried to dissolve a SRTM water layer for province of Quebec and was unable to do it even with 64GB of memory and a SSD and 6 or 7 days of processing. Use the Saga (or Grass) dissolve found in the processing toolbar. It can do it in minutes!</p>
<p dir="ltr">Nicolas Cadieux M.Sc.<br>
Les Entreprises Archéotec inc. <br>
8548, rue Saint-Denis Montréal H2P 2H2<br>
Téléphone: 514.381.5112 Fax: 514.381.4995<br>
www.archeotec.ca</p>
<div class="gmail_quote">On Aug 30, 2015 1:58 PM, "Alex Mandel-2 [via OSGeo.org]" <<a href="/user/SendEmail.jtp?type=node&node=5221846&i=0" target="_top" rel="nofollow" link="external">[hidden email]</a>> wrote:<br type='attribution'><blockquote style='border-left:2px solid #CCCCCC;padding:0 1em' class="quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Kenneth,
<br /><br />How many records, and how much memory do the files take on disc?
<br /><br />Are you joining the SHP and the CSV and then doing Dissolve? Did you
<br />save the joined layer to a new file? Does this shapefile have a spatial
<br />index created? Is the topology of the polygons clean (are there self
<br />intersections, lots of slivers, or overlaps?
<br /><br />Other than saving the intermediate to a file, the next suggestion is to
<br />use Spatialite or Postgis databases.
<br /><br />Keep in mind, that an operation like this is single threaded.
<br /><br />Thanks,
<br />Alex
<br /><br />On 08/30/2015 09:53 AM, Ken Walenga wrote:
<div><div class='shrinkable-quote'><br />> Looking for help. I have an unsimplified ZIP.shp file and want to create my
<br />> own custom boundary files for territories which are a collection of zip
<br />> code areas. I bring in the Zip.shp file and join to a Zip2Terr.csv file on
<br />> the Zip field. When I try to dissolve the TERR_NBR field, the dissolve
<br />> process can take longer than 2 whole days (!). Any ideas on ways to speed
<br />> it up? I have tried using a simplified Zip.shp file, but that results in
<br />> way less than satisfactory boundary files with gaps, etc. Might this be a
<br />> problem with v2.10? Is it possible that I would see better performance
<br />> using an earlier rev?
<br />>
<br />> I am using v2.10 of QGIS, running on a Win7 HP destop machine, quad core, 8
<br />> GB RAM.
<br />>
<br />> Thanks.
<br />>
<br />> ----
<br />> Kenneth Walenga
<br />> Commercial BI & Reporting
<br />> Genentech, A Member of the Roche Group
<br />> US CommOps - USMA Data Services
<br />> "Every moment matters. Making IT happen."
<br />> (O) 650-467-6855
<br />> (F) 650-467-2570
<br />> (M) 650-438-4505
<br />>
<br />>
<br />>
<br />> _______________________________________________
<br />> Qgis-user mailing list
<br />> <a href="/user/SendEmail.jtp?type=node&node=5221843&i=0">[hidden email]</a>
<br />> <a href="http://lists.osgeo.org/mailman/listinfo/qgis-user" target="_top" rel="nofollow" link="external">http://lists.osgeo.org/mailman/listinfo/qgis-user</a><br />>
</div></div>_______________________________________________
<br />Qgis-user mailing list
<br /><a href="/user/SendEmail.jtp?type=node&node=5221843&i=1">[hidden email]</a>
<br /><a href="http://lists.osgeo.org/mailman/listinfo/qgis-user" target="_top" rel="nofollow" link="external">http://lists.osgeo.org/mailman/listinfo/qgis-user</a><br />
<br />
<br />
<hr noshade="noshade" size="1" />
<div style="color:#444;font:12px 'tahoma' , 'geneva' , 'helvetica' , 'arial' , sans-serif">
<div style="font-weight:bold">If you reply to this email, your message will be added to the discussion below:</div>
<a href="http://osgeo-org.1560.x6.nabble.com/Incredibly-slow-performance-using-QGIS-v2-10-tp5221839p5221843.html" target="_top" rel="nofollow" link="external">http://osgeo-org.1560.x6.nabble.com/Incredibly-slow-performance-using-QGIS-v2-10-tp5221839p5221843.html</a>
</div>
<div style="color:#666;font:11px 'tahoma' , 'geneva' , 'helvetica' , 'arial' , sans-serif;margin-top:0.4em;line-height:1.5em">
To start a new topic under Quantum GIS - User, email ml-node+s1560n4125267h38@n6.nabble.com <br />
To unsubscribe from Quantum GIS - User, <a href="http://osgeo-org.1560.x6.nabble.com/template/NamlServlet.jtp?macro=unsubscribe_by_code&node=4125267&code=bmljb2xhcy5jYWRpZXV4QGFyY2hlb3RlYy5jYXw0MTI1MjY3fDYzNDQ4MjQxNg==">click here</a>.<br />
<a href="http://osgeo-org.1560.x6.nabble.com/template/NamlServlet.jtp?macro=macro_viewer&id=instant_html%21nabble%3Aemail.naml&base=nabble.naml.namespaces.BasicNamespace-nabble.view.web.template.NabbleNamespace-nabble.view.web.template.NodeNamespace&breadcrumbs=notify_subscribers%21nabble%3Aemail.naml-instant_emails%21nabble%3Aemail.naml-send_instant_email%21nabble%3Aemail.naml" style="font:9px serif">NAML</a>
</div></blockquote></div>
<br/><hr align="left" width="300" />
View this message in context: <a href="http://osgeo-org.1560.x6.nabble.com/Incredibly-slow-performance-using-QGIS-v2-10-tp5221839p5221846.html">Re: Incredibly slow performance using QGIS v2.10</a><br/>
Sent from the <a href="http://osgeo-org.1560.x6.nabble.com/Quantum-GIS-User-f4125267.html">Quantum GIS - User mailing list archive</a> at Nabble.com.<br/>