Hi Pierre,
Currently I think I'm close to acheiving this.
Ran successfully this query in PostGIS:
SELECT
ST_MapAlgebraExpr(ST_MapAlgebraExpr((ST_Slope(c.rast,1,'32BF')),1,'32BF','((244-[rast])/244)::float'),1,
ST_MapAlgebraExpr(ST_MapAlgebraExpr(a.rast,1, '32BF',
'((67.6499557495117-[rast])/67.6499557495117)'), 1,
ST_MapAlgebraExpr(b.rast,1, '32BF',
'((14052.134765265-[rast])/14052.134765265)'), 1, '([rast1] * 0.5) +
([rast2] * 0.3)::float', '32BF'),1, '([rast1] * 0.2 + [rast2])::float',
'32BF')
FROM
density a, euclidean b, example_postgis20 c
And I'm now trying to view in OpenJump using:
SELECT ST_AsBinary((gv).geom), (gv).val
FROM (SELECT
ST_DumpAsPolygons(ST_MapAlgebraExpr(ST_MapAlgebraExpr((ST_Slope(c.rast,1,'32BF')),1,'32BF','((244-[rast])/244)::float'),1,
ST_MapAlgebraExpr(ST_MapAlgebraExpr(a.rast,1, '32BF',
'((67.6499557495117-[rast])/67.6499557495117)'), 1,
ST_MapAlgebraExpr(b.rast,1, '32BF',
'((14052.134765265-[rast])/14052.134765265)'), 1, '([rast1] * 0.5) +
([rast2] * 0.3)::float', '32BF'),1, '([rast1] * 0.2 + [rast2])::float',
'32BF')) gv
FROM density a, euclidean b, example_postgis20 c) foo
Its returning as no geometry to it.
Can you see where I'm going wrong with this?
This is one of the last pieces in my dissertation.
Kind Regards,
James
-----
GIS Undergraduate
--
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