Hey Standa,
It looks like the high to low output range was causing issues with the
code. So, please try r8393 where I've added a check for the range
direction.
My test query of
{{{
WITH foo AS (
SELECT ST_AddBand(
ST_MakeEmptyRaster(10, 10, 0., 0., 1., -1., 0, 0, 0),
'8BUI', 100., 0
) AS rast
)
SELECT
ST_Reclass(rast, 1, '1-100]:100-1', '8BUI', 0)
FROM foo
}}}
does as expected where the value 100 is set to 1 in the output raster.
-bborie
On 12/13/2011 12:11 AM, Stanislav Vanecek wrote:
Hi Bborie
The SQL is
SELECT
ST_AsTIFF(ST_AddBand(ST_AddBand(ST_AddBand(ST_MakeEmptyRaster(rast),ST_Reclass(rast,1,
'0-2115):255-0'::text, '8BUI'::text,0)),ST_Reclass(rast,1,
'0-2115):255-0'::text, '8BUI'::text,0)),ST_Reclass(rast,1,
'0-2115):255-0'::text, '8BUI'::text,0))
And in this case the result is white rectangle
What I am doing wrong?
Best regards
Standa
-----Original Message-----
From: postgis-users-boun...@postgis.refractions.net
[mailto:postgis-users-boun...@postgis.refractions.net] On Behalf Of Bborie Park
Sent: Monday, December 12, 2011 4:41 PM
To: PostGIS Users Discussion
Subject: Re: [postgis-users] ST_Reclass - oposit direction in reclass
On Mon, Dec 12, 2011 at 6:42 AM, Stanislav Vanecek<s.vane...@dhi.cz> wrote:
Hi
I am using the ST_Reclass to create 3-band TIFF (for graphical
presentation) from 1 band grid 32BF (using algorithm described in 32BF
http://postgis.refractions.net/documentation/manual-svn/RT_ST_Reclass.ht
ml)
The problem is, then for the mapping both intervals in (reclassexpr
text) must be increasing - values from small to high is mapped to
colors from "small to high" = (black to white for example) - and I like
to have them in opposite order.
I am working with the big rasters (2000 x 2000 cells). In this case the
ST_Reclass is already not very fast - and when I try to use map algebra
it was very, very slow.
Did someone have idea how to speed up?
Standa,
Can you post your SQL? I don't think there is anything restricting
you from having your intervals from high to low instead of low to
high, but I could be wrong. ST_Reclass should be faster than
ST_MapAlgebra as all evaluations are done in C instead of going back
and forth with the PostgreSQL server.
-bborie
--
Bborie Park
Programmer
Center for Vectorborne Diseases
UC Davis
530-752-8380
bkp...@ucdavis.edu
_______________________________________________
postgis-users mailing list
postgis-users@postgis.refractions.net
http://postgis.refractions.net/mailman/listinfo/postgis-users