[postgis-users] to get raster values bigger than 20

[Ahmet Temiz]

hello

Using postgis-raster,I want to get raster values bigger than 20.

I tried :

  SELECT ST_AsBinary((ST_DumpAsPolygons(rast)).geom),
(ST_DumpAsPolygons(rast)).val
FROM  (select ST_MapAlgebraExpr(rast,1,'CASE WHEN [rast]  > 20  THEN 1
 ELSE 0 END','0') from slp5 ) as rast;

It is wrong

I will appreciate if you give me a hint

regards




-- 
Ahmet Temiz
Jeoloji Müh.
Afet ve Acil Durum Yönetimi Başkanlığı
Planlama ve Zarar Azaltma Dairesi Başkanlığı


________________________

Ahmet Temiz
Geological Eng.
Information Systems - GIS Group
Disaster and Emergency Management
of Presidency
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