[postgis-users] Postgis raster layer plugin : displaying troubles into Qgis 1.8

Andrew Babiy apratster at gmail.com
Fri Aug 17 10:20:11 PDT 2012

В Fri, 17 Aug 2012 17:52:59 +0200
celati laurent <lcelati at latitude-geosystems.com> пишет:

> Hello,
> I noticed displaying troubles into Qgis 1.8 for one of my Postgis
> raster layer. The raw file (.tif) is a file with a small size and up
> to now i have succeed in importing raster files with a biggest size.
> For information : size of the raw file : 194 MO / Size of generated
> sql file : 44.2 MO.
> I send you by attachment 2 SS : 1/ representation of raw tif file
> into Qgis 1.8 & 2/ representation of Postgis raster layer into Qgis
> 1.8
> Can you help me please to find the cause of the problem?
> In advance, thank you very much for your help.
> Regards.
> Laurent Celati.


I think the roadmap to solve this problem will be:

1) Does Postgis contains correct raster? 
You can check it using JUMP gis and query:

SELECT ST_AsBinary((ST_DumpAsPolygons(rastr)).geom),
 FROM rastr_tbl;

where rastr_tbl your table, rastr - field with rastr.
It will return rastr converted into polygins(and which can be viewed
by JUMP)

If picture you will see will be like on tif - there are correct rastr
in DB. If no - problem in raster convertion.

2) If postgis raster is correct, what Qgis module are you using to show
raster? wktraster? If yes, does it says some errors? 
Maybe, problem in color stretching? Maybe problem in some error with
BAND processing?

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