[postgis-users] Qgis + PostGis. Low operating speed.

[Alex German]

QGis does not pick up overviews.
Separately, overviews are loaded very quickly.
I.e. if I load o_16_t6 in qgis, then the download speed is excellent.
In the properties of the table, there are overviews.

вт, 13 дек. 2022 г. в 12:29, Alex German <gr1047 at gmail.com>:

> [image: image.png]
> SRID in postgis 4326
> [image: image.png]
> SRID in QGis 4326
>
>
> вт, 13 дек. 2022 г. в 12:05, Bo Victor Thomsen <
> bo.victor.thomsen at gmail.com>:
>
>> Is the rasters in same projection (CRS) as the QGIS project ?
>>
>> Med venlig hilsen / Best regards
>>
>> Bo Victor Thomsen
>>
>> Den 13-12-2022 kl. 07:50 skrev Alex German:
>>
>> I did everything as described in the documentation.
>> raster2pgsql -I -C -e -Y -F -s 4326 -t 128x128 -l 2,4,8,16,32
>> "d:\Temp\060 tiff\res\t1.tif" testrastr.t1 | psql.
>> The download is very slow.
>> https://youtu.be/LULngZIs4nc
>>
>> вт, 13 дек. 2022 г. в 09:45, Regina Obe <lr at pcorp.us>:
>>
>>> PostGIS raster sadly doesn’t use the pyramids in the Tifs.  Or if it
>>> does no one told me.
>>>
>>>
>>>
>>> You should build raster overviews using the raster2pgsql –l switch.
>>>
>>> https://postgis.net/docs/using_raster_dataman.html#RT_Raster_Loader
>>>
>>>
>>>
>>> Doc example is this which builds a level 2 and 4 pyramid
>>>
>>> raster2pgsql -I -C -e -Y -F -s 26986 -t 128x128  -l 2,4 bostonaerials2008/*.jpg aerials.boston | psql -U postgres -d gisdb -h localhost -p 5432
>>>
>>>
>>>
>>> QGIS knows how to use the overviews built that way and should be much
>>> faster to view in QGIS
>>>
>>>
>>>
>>> raster2pgsql -s 4326 -t 256x256 -C -I -F "d:\Temp\060
>>> tiff\res\OCG_t1.tif" OCG_t1 -R| psql.
>>>
>>>
>>>
>>>
>>>
>>> *From:* postgis-users [mailto:postgis-users-bounces at lists.osgeo.org] *On
>>> Behalf Of *Alex German
>>> *Sent:* Monday, December 12, 2022 11:34 PM
>>> *To:* PostGIS Users Discussion <postgis-users at lists.osgeo.org>
>>> *Subject:* [postgis-users] Qgis + PostGis. Low operating speed.
>>>
>>>
>>>
>>> Hello everyone!
>>>
>>> I have a GeoTIFF.
>>>
>>> I built the pyramids in an external file using GDAL
>>>
>>> "gdaladdo d:\Temp\060 tiff\res\t1.tif -r lanczos -ro 2 4 8 16 32 64 128
>>> 256 512.
>>>
>>> Uploaded to PostGIS using
>>>
>>> raster2pgsql -s 4326 -t 256x256 -C -I -F "d:\Temp\060
>>> tiff\res\OCG_t1.tif" OCG_t1 -R| psql.
>>>
>>> The number of files is more than 1000.
>>>
>>> When trying to load tables in QGis, the loading is very slow.
>>>
>>> At the same time, downloading to QGis from files is fast. Question. What
>>> is not configured correctly and how to speed up the download to Qgis from
>>> PostGIS?
>>>
>>>
>>>
>>> --
>>>
>>> Alex German
>>>
>>>
>>> _______________________________________________
>>> postgis-users mailing list
>>> postgis-users at lists.osgeo.org
>>> https://lists.osgeo.org/mailman/listinfo/postgis-users
>>>
>>
>>
>> --
>> Алексей Герман
>> 8-905-86-00-416
>>
>> _______________________________________________
>> postgis-users mailing listpostgis-users at lists.osgeo.orghttps://lists.osgeo.org/mailman/listinfo/postgis-users
>>
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>
>
> --
> Алексей Герман
> 8-905-86-00-416
>


-- 
Алексей Герман
8-905-86-00-416
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