[postgis-users] Raster pixel value

[Andreas Forø Tollefsen]

Could this have to do with the tiling of the raster?
I will try to run the same query with a untiled mountain raster to see if
that changes anything.

Btw. When loading a tiled postgis raster into qgis it shows up with many
artifacts and no data areas. The same raster untiled does not show up the
same way.
Qgis bug?

Andreas

2011/11/25 Andreas Forø Tollefsen <andreasft at gmail.com>

> Hi,
>
> Thanks for all of the suggestions. I will do some more testing. However,
> as for suggestion 1 i think the pixel size should be the same as the
> original raster or am I wrong?
>
> Both the mean_mnt_bin raster and the priogrid_land shapefile can be
> downloaded as zip (2 mb) here:
> http://gisintersect.com/mean_mnt_bin.zip
> http://gisintersect.com/priogrid_land.zip
>
> Any help on getting the correct values would be very much appreciated.
>
> My query:
> DROP TABLE IF EXISTS mountain_cell;
>
> SELECT
> a.gid As id,
> (ST_SummaryStats((ST_Union(ST_MapAlgebraExpr(ST_AsRaster(a.cell, b.rast,
> '32BF'), b.rast, 'rast2', '32BF','INTERSECTION','0','0',0))).rast,
> false)).mean As avgmnt
> INTO mountain_cell
> FROM
> priogrid_land a LEFT JOIN
> mountain b
>     ON ST_Intersects(a.cell, b.rast)
> GROUP BY a.gid
> ORDER BY a.gid;
>
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