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I had to make just a few minor adjustments, only about casting types
which you couldn't have know about anyway. Worked well. Many
Thanks.<br>
<br>
<div class="moz-cite-prefix">On 11/3/2016 8:20 AM, Birgit Laggner
wrote:<br>
</div>
<blockquote cite="mid:581B2B70.7010406@thuenen.de" type="cite">
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Hi Stephen,<br>
<br>
here my proposed solution (untested!!)<br>
<br>
DO $$<br>
DECLARE r record; doy date;<br>
BEGIN<br>
<br>
FOR r IN (SELECT DISTINCT ST_Value(rast,x,y) AS obs_date FROM
doy_raster, generate_series(1,(SELECT ST_Width(rast) FROM
doy_raster)) AS x, generate_series(1,(SELECT ST_Height(rast) FROM
doy_raster)) AS y) LOOP<br>
<br>
doy := r.obs_date;<br>
<br>
EXECUTE<br>
'INSERT INTO accum_risk (obs_date, rast)<br>
SELECT '||doy||',<br>
ST_Union(ST_MapAlgebra(a.rast, b.rast,<br>
''CASE WHEN [rast2]='||quote_literal(doy)||'
THEN [rast1] ELSE 0 END'',<br>
''64BF'',''INTERSECTION''),''SUM'')<br>
FROM daily_risk AS a, doy_raster AS b<br>
WHERE a.obs_date BETWEEN '||quote_literal(doy)||'::date -
''60 days''::interval AND<br>
'||quote_literal(doy);<br>
<br>
END LOOP;<br>
<br>
END $$;<br>
<br>
The idea is to loop over the all existing observation dates from
doy_raster and use ST_MapAlgebra to limit the raster cells from
daily_risk raster to those intersecting with raster cells from
doy_raster with the corresponding observation date for the current
loop.<br>
As already mentioned, the code is not tested (because I don't have
similar datasets available)...<br>
<br>
Regards,<br>
<br>
Birgit<br>
<br>
<br>
<div class="moz-cite-prefix">Am 02.11.2016 um 21:51 schrieb
Stephen Crawford:<br>
</div>
<blockquote
cite="mid:4b5de97c-950e-0394-f737-9990578e473f@psu.edu"
type="cite">
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charset=utf-8">
Hi All,<br>
<br>
I am hoping somebody can help me with a query. I have a table
of rasters where each record is date ("obs_date") and raster
containing a risk value of 0 or 1. My easy, successful query
to accumulate the risk values over the previous 60 days is:<br>
<br>
INSERT INTO accum_risk (obs_date, rast)<br>
SELECT '1979-07-15', ST_Union(rast,'SUM')<br>
FROM daily_risk<br>
WHERE obs_date BETWEEN '1979-05-16' AND '1979-07-15';<br>
<br>
My final goal--for which I am asking help--is similar to the
above query, but it will reference another raster table. This
table has for each grid cell a value for the day of year (DOY)
from which the 60 day accumulation should be made. Conceptually:<br>
<br>
FOR EACH doy_cell IN doy_raster<br>
SELECT ST_Union(rast,'SUM')<br>
FROM daily_risk<br>
WHERE obs_date BETWEEN doy-60 AND doy;<br>
<br>
Any help is greatly appreciated.<br>
<br>
Thanks,<br>
Steve<br>
<pre class="moz-signature" cols="72">--
Stephen Crawford
Center for Environmental Informatics
The Pennsylvania State University
<a moz-do-not-send="true" class="moz-txt-link-abbreviated" href="mailto:src176@psu.edu">src176@psu.edu</a>
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<pre class="moz-signature" cols="72">--
Stephen Crawford
Center for Environmental Informatics
The Pennsylvania State University
<a class="moz-txt-link-abbreviated" href="mailto:src176@psu.edu">src176@psu.edu</a>
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