Hi Giovanni, all, On Wed, Jun 20, 2012 at 12:17 PM, G. Allegri <[email protected]> wrote:
> Following a thread I've opened on the grass-users list, I would like to > suggest a proposal to add a flag, to the r.mapcalc command, to discrd > NULL values when evaluating aggregation functions like max(), min(), > mode(), etc. > Looking into the code of, for example., the max() function [1], it seems > that if a NULL value is in the set of the arguments, the result is set to > NULL (if I understand it correctly). > With the proposed flag, I would like to ask r.mapcalc to do not consider > the NULLs, and to the calculations only on the not-NULL subset of values. > Shouldn't it be the default behavior? ciao madi > This would let us do filtering (with row/columns offsets) as it is done in > r.neighbors, where the NULL values are directly discarded. > > giovanni > > [1] > http://trac.osgeo.org/grass/browser/grass/trunk/raster/r.mapcalc/xmax.c > > _______________________________________________ > grass-dev mailing list > [email protected] > http://lists.osgeo.org/mailman/listinfo/grass-dev > -- Dr. Margherita Di Leo
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