Hi Pierre and Celati,
First, I should explain that the GDAL driver may have a reported bug
when trying to read overviews. You may experience performance issues on
GDAL 1.9.
I've reported the bug and it should be fixed on GDAL 1.9.1
http://trac.osgeo.org/gdal/ticket/4649
1/What do you think about overviews values ?
Usually, overviews are assigned dividing the image size by 2. I really
don't know what to expect with custom overviews. GDAL cannot read it at
the moment.
2/According to you, the plugin is abble to display a sql file with a
size of 679 MO ?
It may display with a huge delay. When GDAL's bug is fixed it should be
no problem at all.
3/In native, these data have 5 bands but we need display only 3 bands.
According to you, is it better before importing these data in database
to remove 2 useless bands in order to speed up the display ?
That's probably helpfull. I don't really know about how much it's going
to improve, but if you can avoid 66% table size increase, why not?
4/Is there update regarding the speed problem ( Gdal driver issue).
From the link above I assume that it's under development.
5/Is there another way faster (Gvsig for instance) in displaying postgis
raster data?
I'm not really following GvSIG's development. If they use the same
driver it's most likely that they are running into the same bug.
All the Best,
Mauricio de Paulo
On 07/10/2012 12:24 PM, Pierre Racine wrote:
Mauricio,
We receive many questions regarding the QGIS plugin in the PostGIS user list.
Would you prefer us to tell them to ask their question in the QGIS list (now
GIS Stack Exchange) or would you we willing to follow postgis-users and answer
them when appropriate?
I never use the plugin myself so I am of no help.
Pierre
-----Original Message-----
From: postgis-users-boun...@postgis.refractions.net
[mailto:postgis-users-boun...@postgis.refractions.net] On Behalf Of celati
laurent
Sent: Tuesday, July 10, 2012 7:03 AM
To: postgis-users@postgis.refractions.net
Subject: [postgis-users] Postgis raster data display
Hello,
I'm trying to display "Raster postgis data" via Qgis ("Load Postgis
Raster Layer"). It works but it's a bit slow!
These raster are 11 Rapideye satellite images with 5 bands in native. I
defined following overviews for each data : 3,9,27,81,243
Size of smallest SQL file : 270 MO
Size of biggest SQL file : 679 MO
1/What do you think about overviews values ?
2/According to you, the plugin is abble to display a sql file with a
size of 679 MO ?
3/In native, these data have 5 bands but we need display only 3 bands.
According to you, is it better before importing these data in database
to remove 2 useless bands in order to speed up the display ?
4/Is there update regarding the speed problem ( Gdal driver issue).
5/Is there another way faster (Gvsig for instance) in displaying postgis
raster data?
Thank you to throw light for me.
Regards.
Laurent Celati.
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