On vendredi 17 novembre 2017 23:14:19 CET Patrick Dunford wrote: > I understand (especially with the other comments about the functionality > and having to wait for images to be retrieved from servers) what you > guys are trying to achieve with this feature, but in my project the > rasters I have loaded cover hundreds of square kilometres, and Qgis > caches all of them, regardless of how far they are from the particular > point where I am working on a map. >
If your rasters are in the same projection and same resolution, did you consider building a virtual .VRT catalog from them ? (or group them in catalogs per projection and resolution). That could reduce the number of layers. > On 17/11/17 21:56, Alessandro Pasotti wrote: > > Maybe a crazy idea, but if this proves to be an issue, what about a > > monitoring process that prompts the user to disable this feature when > > memory goes over a certain threshold? > > > > On Fri, Nov 17, 2017 at 8:21 AM, Patrick Dunford > > > > <[email protected] <mailto:[email protected]>> wrote: > > Most of them are geoJpeg, there are a smaller number of geoTiff > > > > On 17/11/17 20:10, Matthias Kuhn wrote: > >> Thanks, that's an interesting information. > >> > >> What datatype are your rasters? > >> > >> On 11/17/2017 03:53 AM, Patrick Dunford wrote: > >>> With the second command > >>> > >>> iface.mapCanvas().setPreviewJobsEnabled(False) > >>> > >>> when I run that command it drops back to 16 GB > >>> > >>> On 16/11/17 23:15, Matthias Kuhn wrote: > >>>> Hi Patrick, > >>>> > >>>> Would be interesting to do this test with previews enabled and > >>>> disabled. Then we'll see if it's actually the previews or some > >>>> other mechanism that is causing this. > >>>> > >>>> IIRC only a composite image is saved in the preview jobs and > >>>> not each layer separately, but that's just what I remember and > >>>> not evidence based. > >>>> > >>>> You can enable them in the python console with > >>>> > >>>> iface.mapCanvas().setPreviewJobsEnabled(True) > >>>> > >>>> and disable with > >>>> > >>>> iface.mapCanvas().setPreviewJobsEnabled(False) > >>>> > >>>> Thanks for a feedback > >>>> > >>>> Matthias > >>>> > >>>> On 11/16/2017 08:42 AM, Patrick Dunford wrote: > >>>>> In my current project using Qgis 2.99, turning off the rasters > >>>>> uses 16 GB, turning them on uses 52 GB > >>>>> > >>>>> I do not believe it is independent from the number of layers > >>>>> that are being displayed. > >>>>> > >>>>> Previous versions of the software did not cache every single > >>>>> raster (the number of rasters actually being displayed on the > >>>>> canvas at any one time is a small fraction of the total number > >>>>> in the project) > >>>>> > >>>>> On 16/11/17 20:11, Matthias Kuhn wrote: > >>>>>> Hi Patrick, > >>>>>> > >>>>>> This uses some memory (~ canvas width pixels * canvas height > >>>>>> pixels * 8 preview images * 32 bit RGBA), so let's assume 50 > >>>>>> MB to 100 MB. > >>>>>> > >>>>>> This consumption is independent from the number or type of > >>>>>> layers. > >>>>>> > >>>>>> Matthias > >>>>>> > >>>>>> On 11/16/2017 08:02 AM, Patrick Dunford wrote: > >>>>>>> So to put it another way this is the reason why Qgis wants > >>>>>>> to use a huge amount of memory (40 GB) when I have a lot of > >>>>>>> raster images loaded in the background. > >>>>>>> > >>>>>>> On 16/11/17 18:56, Tim Sutton wrote: > >>>>>>>> Hi > >>>>>>>> > >>>>>>>>> On 16 Nov 2017, at 04:35, Patrick Dunford > >>>>>>>>> <[email protected] <mailto:[email protected]>> > >>>>>>>>> wrote: > >>>>>>>>> > >>>>>>>>> What is this "preview job" function? > >>>>>>>> > >>>>>>>> Its application logic to prefetch / pre-render offscreen > >>>>>>>> content in anticipation of user panning the map. > >>>>>>>> > >>>>>>>> Regards > >>>>>>>> > >>>>>>>> Tim > >>>>>>>> > >>>>>>>>> _______________________________________________ > >>>>>>>>> QGIS-Developer mailing list > >>>>>>>>> [email protected] > >>>>>>>>> <mailto:[email protected]> > >>>>>>>>> List info: > >>>>>>>>> https://lists.osgeo.org/mailman/listinfo/qgis-developer > >>>>>>>>> <https://lists.osgeo.org/mailman/listinfo/qgis-developer> > >>>>>>>>> Unsubscribe: > >>>>>>>>> https://lists.osgeo.org/mailman/listinfo/qgis-developer > >>>>>>>>> <https://lists.osgeo.org/mailman/listinfo/qgis-developer> > >>>>>>>> > >>>>>>>> — > >>>>>>>> > >>>>>>>> > >>>>>>>>
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