[postgis-users] [Raster] MNT 250 IGNF data import problem

Tue Oct 22 08:44:39 PDT 2013

Hugues, Pierre,

Le mardi 22 octobre 2013 14:20:28 Hugues François a écrit :
> Hello,
> 
> I'm sorry but I don't understand why you are looking for numerous band with
> a mnt. In my mind it has only one single band made of elevation values.

Because I did a quick test and copied past previous SQL requests and I did not 
clean it before! Of course you can remove the next 2 bands which don't exist 
but the first one should have correct statistic.

Thanks Pierre to let me know the logical ;)

> Rasters are not so easy to display correctly with qgis or another desktop
> software.
I already see raster data in QGIS and if there is some issue, I will be 
pleased to understand them!

As far as I understand, gdal is wrong somewhere. I get this message in QGIS 
log:
Warning: RasterIO error: Error retrieving raster data from database

which come from gdal source code (postgresql provider).

Looking in the pgsql log I get a lot of wrong request:
        SQL function "st_polygonfromtext" statement 1
2013-10-22 17:38:47 CEST STATEMENT:  SELECT st_band(rast, 1), st_width(rast), 
st_height(rast), st_bandpixeltype(rast, 1), st_bandnodatavalue(rast, 1), 
st_scalex(rast), st_scaley(rast), st_upperleftx(rast), st_upperlefty(rast) 
FROM raster.mnt250 WHERE st_intersects(rast, 
st_polygonfromtext('POLYGON((89875,00000000000000000 
7120125,00000000000000000, 4789875,00000000000000000 
7120125,00000000000000000, 4789875,00000000000000000 
2720125,00000000000000000, 89875,00000000000000000 2720125,00000000000000000, 
89875,00000000000000000 7120125,00000000000000000))', 2154))

As you can see POLYGON is made of wrong WKT: number is using the comma as the 
decimal separator which is wrong in WKT (should be .)

> On my part, when i want to make tests with or without walues, I
> prefer to use st_dumpaspolygons or st_envelope. You may find some
> information on this, maybe a bit dated now, page :
> http://trac.osgeo.org/postgis/wiki/WKTRaster (scroll down to Displaying
> postgis rasters).

Indeed and QGIS is listed ;) but unfortunately raster plugin is for QGIS 1.x.

I tried the SQL resquest with st_dumpaspolygons but except a list of "NOTICE  
Ring Self-intersection at or near point [..] [..]" nothing interesting ;)

Thanks both for your reply,

Y.
> 
> Hugues.
> 
> 
> 
> 
> -----Original Message-----
> From: postgis-users-bounces at lists.osgeo.org
> [mailto:postgis-users-bounces at lists.osgeo.org] On Behalf Of Yves Jacolin
> Sent: Tuesday, October 22, 2013 1:48 PM
> To: PostGIS Users Discussion
> Subject: [postgis-users] [Raster] MNT 250 IGNF data import problem
> 
> Hello list,
> 
> I am currently trying importing french IGN MNT 250 into a postgis database
> (v 2.0.1):
> 
> raster2pgsql -b 1 -s 2154 -I -C -t 100x100 MNT250_L93_FRANCE.ASC
> raster.mnt250
> | psql -d formation
> 
> When testing my raster layer I get strange result:
> SELECT rid, band, (stats).*
> FROM (SELECT rid, band, ST_SummaryStats(rast, band) As stats
>     FROM raster.mnt250 CROSS JOIN generate_series(1,3) As band
>      WHERE rid=2) As foo;
> 
> NOTICE:  Invalid band index (must use 1-based). Returning NULL
> CONTEXT:  SQL function "st_summarystats" statement 1 [several time]  rid |
> band | count | sum | mean | stddev | min | max
> -----+------+-------+-----+------+--------+-----+-----
>    2 |    1 | 10000 |   0 |    0 |      0 |   0 |   0
>    2 |    2 |       |     |      |        |     |
>    2 |    3 |       |     |      |        |     |
> 
> QGIS can't display my layer (well the layer seems white) and if I request my
> layer I get some weird value (224964728 for example).
> 
> In QGIS log, I have:
> 
> ERROR 1: PG: dbname=formation host=localhost user=yjacolin password=
> port=5432 mode=2 schema=raster table=mnt250, band 1: IReadBlock failed at X
> offset 32, Y offset 29 ERROR 1: Error retrieving raster data from database
> 
> Any idea why this is not working as expected?
> 
> When I use raster2pgsql I get this message:
> raster2pgsql: /usr/local/lib/libgdal.so.1: no version information available
> (required by raster2pgsql)
> 
> I built gdal but not postgis.
> 
> Thanks,
> 
> Y.
> --
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-- 
Responsable Formation et Support
Camptocamp France SAS
Savoie Technolac, BP 352
73377 Le Bourget du Lac, Cedex
Tel (France) : +33 4 79 26 57 98
Tel (Suisse) : 021 619 10 43 (new)
Mob. : +33 6 18 75 42 21
Fax : 04 79 70 15 81
Mail : yves.jacolin at camptocamp.com
http://www.camptocamp.com