[postgis-users] No intersection between two rasters notice

[Francois Hugues]

Hi everyone,

I'm facing a new difficulty with rasters. This time with
st_MapAlgebraExpr (the whole query is below). I have this notice when I
try to cross two rasters with exactly similar tiles.
NOTICE:  The two rasters provided have no intersection.  Returning no
band raster

To avoid to cross tiles with others where there were effectively no
intersection I tried the where clause "where st_intersects(rast1,
rast2)" but the problem is not really solved. Is it because of adjacent
tiles ?

Is there a more effective (and faster) way to use mapalgebra and to
avoid this creation of empty tiles which prevent to use st_convexhull
(and every function which use convexhull) ?

Hugues.

select alti.rid, st_mapalgebraexpr(alti.rast, slopes.rast,
'[rast1]*[rast2]', '32BF', 'NULL', 'NULL', 'NULL') rast
from rasters.alti_cons_ign_alpes alti, rasters.slopes_alpes slopes
where st_intersects(alti.rast, slopes.rast)