[GRASS-user] t.rast.aggregate help

[Maria Elena Martinotti]

Hallo everybody, 


I am trying to aggregate some time-stamped raster (placed in
an initial space-time dataset) but I have some problems; each raster represents
a 1h-cumulated rainfall, so I have something like this:


raster1 | start_time 2014-09-04  12:00:00 | end_time 2014-09-04  13:00:00

raster2 | start_time 2014-09-04  13:00:00 | end_time 2014-09-04  14:00:00

etc


I would like to aggregate from a certain datetime backward adopting
different granularities (2 hours, 3 hours, 4 hours, 5hours and 6 hours) but not
in a “massive” way, I  just need the first aggregation for each granularity. I
came up with something like this:


for i in `seq 2 1 6` ;

do t.rast.aggregate -- o input=initial_dataset  output=${i}h_aggregate  method=sum basename=${i}h_aggregate   granularity="$i hours"   sampling=contains   where="start_time = datetime('2014-09-04
 14:00:00','-$i hours') and end_time
<= '2014-09-04  12:00:00'");

done;


For i=2 for example, I would like to sum up raster1 and
raster2; if I ask for a t.rast.list of the 2h_aggregate dataset, star and end
time seem correct but if I do a query directly on one point of the raster maps
(raster1, raster2 and the output of the aggregation) I see that the results aren’t
correct. It seems that it didn’t perform the
aggregation.  It's because of the where query? 


Thanks for your help.

Maria Elena


 		 	   		  
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