[postgis-devel] [PostGIS] #1317: [raster] CASE expression causes ST_MapAlgebra for 2 raster to fail

[PostGIS]

#1317: [raster] CASE expression causes ST_MapAlgebra for 2 raster to fail
----------------------------+-----------------------------------------------
 Reporter:  pracine         |       Owner:  pracine      
     Type:  defect          |      Status:  new          
 Priority:  medium          |   Milestone:  PostGIS 2.0.0
Component:  postgis raster  |     Version:  trunk        
 Keywords:                  |  
----------------------------+-----------------------------------------------
Description changed by pracine:

Old description:

> This query:
>
> {{{
> SELECT ST_MapAlgebraExpr(ST_AddBand(ST_MakeEmptyRaster(4, 4, 0, 0, 1, 1,
> 0, 0, -1), '32BF'::text, 6, -1), 1,
>                          ST_AddBand(ST_MakeEmptyRaster(4, 4, 0, 0, 1, 1,
> 0, 0, -1), '32BF'::text, 4, -1), 1,
>                          'CASE WHEN rast2 > 0 THEN rast1 / rast2 ELSE
> NULL END'::text,
>                          NULL::text,
>                          'UNION'::text,
>                          NULL::text,
>                          NULL::text,
>                          NULL::double precision)
> }}}
>
> produces this error"
>
> {{{
> ERROR:  column "rast2" does not exist
> LINE 1: SELECT (CASE WHEN $2 > 0 THEN $1 / RAST2 ELSE NULL END)::dou...
>                                            ^
> QUERY:  SELECT (CASE WHEN $2 > 0 THEN $1 / RAST2 ELSE NULL END)::double
> precision
>
> ********** Error **********
>
> ERROR: column "rast2" does not exist
> SQL state: 42703
> }}}
>
> There seems to be a problem when parsing CASE expressions...
>
> I was testing ST_Union()...

New description:

 This query:

 {{{
 SELECT ST_MapAlgebraExpr(ST_AddBand(ST_MakeEmptyRaster(4, 4, 0, 0, 1, 1,
 0, 0, -1), '32BF'::text, 6, -1), 1,
                          ST_AddBand(ST_MakeEmptyRaster(4, 4, 0, 0, 1, 1,
 0, 0, -1), '32BF'::text, 4, -1), 1,
                          'CASE WHEN rast2 > 0 THEN rast1 / rast2 ELSE NULL
 END'::text,
                          NULL::text,
                          'UNION'::text,
                          NULL::text,
                          NULL::text,
                          NULL::double precision)
 }}}

 produces this error:

 {{{
 ERROR:  column "rast2" does not exist
 LINE 1: SELECT (CASE WHEN $2 > 0 THEN $1 / RAST2 ELSE NULL END)::dou...
                                            ^
 QUERY:  SELECT (CASE WHEN $2 > 0 THEN $1 / RAST2 ELSE NULL END)::double
 precision

 ********** Error **********

 ERROR: column "rast2" does not exist
 SQL state: 42703
 }}}

 There seems to be a problem when parsing CASE expressions...

 I was testing ST_Union()...

--

-- 
Ticket URL: <http://trac.osgeo.org/postgis/ticket/1317#comment:1>
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