[postgis-users] ST_Mapalgebra

[Bborie Park]

On Mon, Nov 21, 2011 at 7:02 AM, Joan <wamaithajoan at gmail.com> wrote:
> Hello,
>
> When I run the following query
> select ST_MapAlgebra(r1.rast, r2.rast, "rast1 + rast2") from (select
> r1.rast, r2.rast from r1, r2) as foo limit 10;
> I get this error
> ERROR: column "rast + rast" does not exist
> LINE 1: ...t * from (select ST_MapAlgebra(r1.rast, r2.rast, "rast + ra...
> ^
> What could be the problem? What is the correct syntax for st_mapalgebra?
> I have PostGIS installed the version updated on 18th Nov 2011.
>
> Joan

Hey Joan,

You'll want to use ST_MapAlgebraExpr or ST_MapAlgebraFct.

http://postgis.refractions.net/documentation/manual-svn/RT_reference.html#Raster_Processing

-bborie

-- 
Bborie Park
Programmer
Center for Vectorborne Diseases
UC Davis
530-752-8380
bkpark at ucdavis.edu