Thanks Andreas, Glad to know its not just me as well :-)
Brent --- On Tue, 9/1/09, Andreas Neumann <[email protected]> wrote: > From: Andreas Neumann <[email protected]> > Subject: Re: [Qgis-user] QGIS performance problem > To: [email protected] > Cc: [email protected] > Date: Tuesday, September 1, 2009, 6:31 AM > Hi Brent, > > I have similar behaviour. It happens if polygons with lots > of vertices > are involved. Things get even worse if you try to print > this data with > high resolution. > > Marco Hugentobler and Jürgen Fischer are already working > on this issue > these days. They can also better explain the issues we are > running into > - seems to be qt and clipping related when bounding boxes > of big > polygons are touched when zooming in or printing on high > resolutions. > > I am glad to hear that I am not the only person > experiencing these > problems - seems to be a real issue. > > Andreas > > [email protected] > wrote: > > Hi, > > > > I have a PostGIS table & shapefile of the New > Zealand coast (1:50,000) > > > > If I open this table it plots in a fraction of a > second, pretty much as expected, with similar speeds for > both the shapefile & table. > > > > However, if I zoom in, the redraw takes three minutes > or more. > > > > While I'm waiting for the refresh, Qgis is showing > 100% cpu load, postgres isn't showing at all (top). On an > AMD dual core 3.2Ghz cpu with 8Gb ram it should not take > anything like this long, and with earlier versions of Qgis > (pre 1.0) it was much faster. > > > > Performance is similar with both table & shapefile > data sources, so it does not seem Postgres related. > > > > However, plotting lines, points or polygons with tens > of thousands of features rendered works well, it seems to > primarily be polygons with many vertices (not even any > holes) that are the problem. > > > > OpenSuse 11.1, Qgis 1.2.0, Postgis table described > below, only 3 features/records, indexed & vacuumed. > > > > > > Does anyone have any idea what may be the issue? > > > > I can provide an ssh login if anyone wants to test > this for themselves. > > > > > > Thanks, > > > > Brent Wood > > > > > > > > > > > > > > > > Table "public.coast_poly" > > Column | > Type > | > Modifiers > > > > > ---------+-----------------------+---------------------------------------------------------- > > gid | integer > | not > null default nextval('coast_poly_gid_seq'::regclass) > > id | bigint > | > > fid | bigint > | > > name | character varying(42) | > > geom_ll | geometry > | > > Indexes: > > "coast_poly_pkey" PRIMARY KEY, > btree (gid) > > "coast_poly_geom_ll_gist" gist > (geom_ll) > > Check constraints: > > "enforce_dims_geom_ll" CHECK > (ndims(geom_ll) = 2) > > "enforce_geotype_geom_ll" > CHECK (geometrytype(geom_ll) = 'MULTIPOLYGON'::text OR > geom_ll IS NULL) > > "enforce_srid_geom_ll" CHECK > (srid(geom_ll) = 4326) > > > > > > _______________________________________________ > > Qgis-user mailing list > > [email protected] > > http://lists.osgeo.org/mailman/listinfo/qgis-user > > > > _______________________________________________ Qgis-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/qgis-user
