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 _______________________________________________ Qgis-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/qgis-user
