> boun...@postgis.refractions.net] On Behalf Of JamesH
> Sent: Wednesday, April 25, 2012 7:34 PM
> To: postgis-users@postgis.refractions.net
> Subject: Re: [postgis-users] MapAlgebra on three Rasters
>
> Sorry, I should have explained what I'm trying to do with the query.
>
> I&#
Have resolved this MapAlgebra issue, the issue was with the slope surface, I
was trying to produce as a 32BF but it needed to be 32BSI to be visible.
Calculation and resample ran effectively using:
CREATE TABLE Metro_location2 AS(
SELECT
ST_MapAlgebraExpr(ST_Resample(a.rast, b.rast), 1, b
I have refined my query so that I am using MapAlgebraExpr on the normalised
distance and density rasters and exporting as a new table.
Then I am using a second, new MapAlgerbaExpr query with this table and the
normalised slope surface.
However it is returning, 'The two rasters provided do not have
Sorry, I should have explained what I'm trying to do with the query.
I'm taking the two rasters density and euclidean, normalising them both
before multiplying normalised density by 0.5, multiplying normalised
euclidean by 0.3 and then adding these together.
Then I am producing a slope surface,
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])/67.6
refractions.net
> Subject: [postgis-users] MapAlgebra on three Rasters
>
> Hi all,
>
> I have three Raster's stored in seperate tables which I am looking to
> perform a weighted calculation on all three to produce a single Raster as an
> output (or a visualisati
Currently, I am using:
CREATE TABLE map2 AS(
SELECT
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', '32
Hi all,
I have three Raster's stored in seperate tables which I am looking to
perform a weighted calculation on all three to produce a single Raster as an
output (or a visualisation through OpenJump or Quantum).
The calculation I am attempting is basically:
(raster1 * 0.2) + (raster2 * 0.5) + (r
