Spinning disks can be significantly slower than an SSD :( However, I've opened 10GB, 3-band rasters off spinning platter disks in seconds, so :-\ Some calculations on band cutoffs and things can take a while if I ask it to calculate those.
On Thu, Jul 30, 2015 at 9:50 AM, Nicolas Cadieux < [email protected]> wrote: > Hi, > > I have been opening rasters that are much bigger than that lately with no > trouble at all. It does take some time but not hours. I have bigger file > (80-300GB) but with one band only. I do use a SSD to help out but works > with a usb3 drive also. > > The obvious is to check for to see if there is a problem with the hardware > (memory, CPU, drive) and to make sure you are not opening the file from a > file server (a virtual drive) but from a local hard drive (not a USB key) > or a failing HD. > > Try zooming on the zone using a small polygons as a reference, before > opening the raster. Try disabling the "screen render" before opening the > raster (right lower corner or Option\Rendering\Rendering behavior. > > An other potential problem is the way the tiff was created. If, for > example the file was created with gdal-Grid (interpolation), then by > default, the file was created with an origin from the bottom-left and not > upper-left. > > Try resaving the file in QGIS. Try using the QGIS usual method of saving > rasters and also try using gdal-warp with no parameters > (raster/projections/warp) (that with change the file origin) then reopen > the file. > > Nicolas Cadieux M.Sc. > Les Entreprises Archéotec inc. > 8548, rue Saint-Denis Montréal H2P 2H2 > Téléphone: 514.381.5112 Fax: 514.381.4995 > www.archeotec.ca > On Jul 30, 2015 7:49 AM, "Radim Blazek-2 [via OSGeo.org] " <[hidden email] > <http:///user/SendEmail.jtp?type=node&node=5217781&i=0>> wrote: > > On Thu, Jul 30, 2015 at 11:36 AM, Andrea Peri <<a > href="/user/SendEmail.jtp?type=node&node=5217747&i=0">[hidden > email]> wrote: > > Hi Radim, > > thx for hint. > > > > I try to set the contrast enhancement to NO STRETCH > > and > > Limits to minimum / maximum , > > Apparently seem to have no result. The qgis is locked in opening of > > raster, but of course I should wait for some hours to see if some > > improvements is occursed. > > You can try to uncheck Options > Canvas & Legend > Layer Legend > > Create raster icons > but I don't think that it could help if zoom/pan is fast, so it seems > that there are overviews (pyramids). In fact, even with cumulative cut > it should not be slow if there are overviews because default cut > calculation is using estimated histogram (250000 pixels). > > The file is on local hard disk? > > Do you see what is happening from debug output? > > If you save a project with the raster, the next load of the project is > fast? > > Radim > > > > A. > > > > > > 2015-07-30 9:52 GMT+02:00 Radim Blazek <<a > href="/user/SendEmail.jtp?type=node&node=5217747&i=1">[hidden > email]>: > >> On Thu, Jul 30, 2015 at 9:19 AM, Andrea Peri <<a > href="/user/SendEmail.jtp?type=node&node=5217747&i=2">[hidden > email]> wrote: > >>> Hi, > >>> > >>> I have a GeoTiff raster of 24Gbyte, floating point (Float64) with 11 > >>> bands and fomat geotiff. > >>> > >>> When try to open it with qgis 2.8.1 I see it take a really uge time to > >>> open it (about 10 hours). > >>> Initially I guess that was a time due to the huge dimension, but after > >>> the qgis show it. > >>> I notice that it is reallyquickly to zoom and pan. > >>> I don't understand why this difference between the open time and > zoom/pan time. > >>> > >>> My first suspect was that qgis want to calculate the statistics in > first open. > >>> But after a check with gdalinfo I see the statistics are available > >>> also in original tiff. > >> > >> QGIS defaults are stretch to 2/98% cut, try to set in > >> Options > Rendering > Rasters > >> Contrast enhancement: No stretch or Limits: Minimum / maximum > >> > >> Radim > >> > >> > >>> So I dont know really why it take so more time to open it. > >>> > >>> I hope to find some setting to reduce the pen time for this kind of > images. > >>> > >>> Thx, > >>> > >>> A. > >>> > >>> -- > >>> ----------------- > >>> Andrea Peri > >>> . . . . . . . . . > >>> qwerty àèìòù > >>> ----------------- > >>> _______________________________________________ > >>> Qgis-user mailing list > >>> <a > href="/user/SendEmail.jtp?type=node&node=5217747&i=3">[hidden > email] > >>> http://lists.osgeo.org/mailman/listinfo/qgis-user > > > > > > > > -- > > ----------------- > > Andrea Peri > > . . . . . . . . . > > qwerty àèìòù > > ----------------- > _______________________________________________ > Qgis-user mailing list > <a > href="/user/SendEmail.jtp?type=node&node=5217747&i=4">[hidden > email] > http://lists.osgeo.org/mailman/listinfo/qgis-user > > ------------------------------ > If you reply to this email, your message will be added to the discussion > below: > > http://osgeo-org.1560.x6.nabble.com/Slow-to-open-huge-rasters-tp5217691p5217747.html > To start a new topic under Quantum GIS - User, email > [email protected] > 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 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 > <http://osgeo-org.1560.x6.nabble.com/template/NamlServlet.jtp?macro=macro_viewer&id&%2361;instant_html%21nabble%3Aemail.naml&base&%2361;nabble.naml.namespaces.BasicNamespace-nabble.view.web.template.NabbleNamespace-nabble.view.web.template.NodeNamespace&breadcrumbs&%2361;notify_subscribers%21nabble%3Aemail.naml-instant_emails%21nabble%3Aemail.naml-send_instant_email%21nabble%3Aemail.naml>" > style="font:9px serif">NAML > > > ------------------------------ > View this message in context: Re: Slow to open huge rasters > <http://osgeo-org.1560.x6.nabble.com/Slow-to-open-huge-rasters-tp5217691p5217781.html> > Sent from the Quantum GIS - User mailing list archive > <http://osgeo-org.1560.x6.nabble.com/Quantum-GIS-User-f4125267.html> at > Nabble.com. > > _______________________________________________ > Qgis-user mailing list > [email protected] > http://lists.osgeo.org/mailman/listinfo/qgis-user >
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