Hi Micha and Victor, Thanks for your reply. I will try R.Series module of GRASS. I think this is what I am looking for...
-Leo On Apr 14, 2014 5:57 PM, "Victor Olaya" <[email protected]> wrote: > Using the Processing raster calculator to sum up layers should > correctly handle no-data values, and leave a no-data value in those > cells for which one of such values appears in the sum. > > 2014-04-14 11:29 GMT+02:00 Micha Silver <[email protected]>: > > > > On 14/04/2014 06:19, Leo Kris Palao wrote: > > > > Hi ALL QGIS users, > > > > Good day! > > > > I want to calculate the sum of the raster layers, but I want to ignore > the > > no data values in the calculation. This is similar to cell statistics > > (spatial analyst) enable the Ignore NoData in calculations (optional) in > > ArcGIS. > > > > > > You can choose the GRASS module "r.series". Regarding no data cells, they > > are handled as follows (from the manual page): > > > > Without -n flag, the complete list of inputs for each cell (including > NULLs) > > is passed to the aggregate function. Individual aggregates can handle > data > > as they choose. Mostly, they just compute the aggregate over the non-NULL > > values, producing a NULL result only if all inputs are NULL. > > > > So if you use "method=sum" you'll get an output raster which sums all non > > null input cells. > > > > > > > > So far I am doing all my process in QGIS (batch processing is great in > the > > processing toolbox). This is the only step that I am using ArcGIS > because I > > cannot find the right tool in QGIS. > > > > Thanks in advance for any help. > > > > -Leo > > > > This mail was received via Mail-SeCure System. > > > > > > _______________________________________________ > > Qgis-user mailing list > > [email protected] > > http://lists.osgeo.org/mailman/listinfo/qgis-user > > This mail was received via Mail-SeCure System. > > > > > > > > > > _______________________________________________ > > Qgis-user mailing list > > [email protected] > > http://lists.osgeo.org/mailman/listinfo/qgis-user >
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