Hello,
the issue is not with the performance drawing the raster, it is with the
system only being able to have a certain number of file based rasters
loaded in a project before it will crash.
On 22/11/19 11:08 AM, Alexandre Neto wrote:
AFAIK,
WMST creates pyramids in cache as needed, hence it may do a better
balance between disk usage and performance. You can control the number
of pyramid layers you create and the compression format of it to save
some space. But having raster files with 4000x4000 pixels with no
pyramids will make a full read of the raster file to show even only a
bit of it... That will make QGIS performance really poor.
Thereºs this blog post from 2010 that does some comparison
between several formats and their sizes and performances. It's in
portuguese, but I think you can find ways of translating it.
https://blog.viasig.com/2010/01/mosaicos-de-imagens-em-mapserver-com-gdal/
Hope it helps
Alexandre Neto
On Thu, Nov 21, 2019 at 2:05 PM Patrick Dunford
<enzedrailm...@gmail.com <mailto:enzedrailm...@gmail.com>> wrote:
Building pyramids gobbles up heaps of disk space. I tried pyramids
on 157 MB layer, which created an extra file 1.6 GiB.
I can't see the WMTS building lots of temporary file pyramids
using up disk
On 18/11/19 10:50 PM, Alexandre Neto wrote:
Hi Patrick,
Sorry for asking, did you create pyramids (overlays) for your
raster "tiles"?
See more information about pyramids on QGIS official documentation:
https://docs.qgis.org/3.4/en/docs/user_manual/working_with_raster/raster_properties.html#pyramids-properties
To create pyramids on many files, it's probably better to use
GDAL directly to process all files in a folder:
https://gdal.org/programs/gdaladdo.html
My feeling is that the WMS service is doing that for you, and
that's the reason why it works well with a service.
Alexandre Neto
QGIS Support
www.qcooperative.net <http://www.qcooperative.net>
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