[Qgis-user] Slow rendering of vrt

[Even Rouault]

Selon Etienne Tourigny <etourigny.dev at gmail.com>:

> It would be nice to have this bultin to gdalbuildvrt (as an optin of
> course) - could the authors make a patch?

For a *byte* data type, which must be the common case, why wouldn't QGIS just
use min=0 and max=255 when statistics are not computed ?

>
> Regards,
> Etienne
>
> On Thu, Aug 23, 2012 at 7:34 AM, Micha Silver <micha at arava.co.il> wrote:
> > On 23/08/2012 11:33, Giovanni Manghi wrote:
> >>
> >> http://trac.osgeo.org/gdal/wiki/CatalogueForQIS
> >
> >
> > Magic! Many thanks, and also to Andrea Peri for posting the python code.
> > In windows I had to run it as: " python computestats.py -approx
> > <filename.vrt> "
> >>
> >> it would be very nice to have this added as tool directly in QGIS...
> >>
> >> cheers
> >>
> >>
> >> -- Giovanni --
> >>
> >>
> >> On Thu, 2012-08-23 at 11:27 +0300, Micha Silver wrote:
> >>>
> >>> Hello all:
> >>>
> >>> I have a batch of over 100 raster tiles in ecw format. Each is 50 -
> >>> 100 MB in size. When I choose 20 or so files to load they appear
> >>> (render) very quickly - in a matter of a few seconds or less. If I
> >>> create a vrt of that same batch of tiles, it takes a long time to
> >>> first render - upwards of 15 - 30 seconds.  Once the vrt is loaded
> >>> response is excellent (zooming, etc). But that initial delay is a bit
> >>> annoying. Anything I can do to improve it? (QGIS 1.8, Win 7 64 bit)
> >>>
> >>> Many thanks,
> >>> Micha
> >>>
> >>> --
> >>> Micha Silver
> >>> 052-3665918
> >>> _______________________________________________
> >>> Qgis-user mailing list
> >>> Qgis-user at lists.osgeo.org
> >>> http://lists.osgeo.org/mailman/listinfo/qgis-user
> >>
> >>
> >>
> >> This mail was received via Mail-SeCure System.
> >>
> >>
> >
> >
> > --
> > Micha Silver
> > 052-3665918
> >
> > _______________________________________________
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