Hello Francesco, Markus I find the possibility of getting statistics for only a certain fraction of a neighbourhood really interesting and I like Markus' idea as it is more general and allows for more use cases š¤ Count me in for testing ;)
Vero El mar, 31 ene 2023 a las 15:48, Markus Metz (<markus.metz.gisw...@gmail.com>) escribiĆ³: > Hi Francesco, > > the proposed change to r.neighbors is interesting, but maybe too specific: > you have introduced two new functions, and many more functions would be > needed to e.g. get the filtered standard deviation or median. > > Therefore I suggest adding some filtering option to r.neighbors consisting > of a filtering function and a comparison operator. The filtering function > would be any of the currently supported neighborhood functions returning > some value. The comparison operator would be one of gt, ge, le, lt (>, >=, > <=, <). r.neighbors would then first get the result value of the filtering > function, then set all values in the neighborhood to NULL that do not > fulfil the condition "value <comparison operator> <result value">, then > call the actual neighborhood operation with the filtered values. This would > be more flexible, because the user can freely combine a neighborhood filter > function with a neighborhood operation. > > Makes sense? > > > On Wed, Jan 25, 2023 at 10:55 AM Francesco P. Lovergine < > fran...@debian.org> wrote: > >> Hi, >> >> for some specific needs of a research project, I had to make a little >> change to r.neighbors (the target version was 7.8.5 but that's not >> essential). >> >> Essentially, the idea behind is computing first order statistics on >> partial >> populations as identified by selected quantiles (samples >= or <= of a >> threshold value of quantile). >> >> For that, I introduced average_ge_quantile and average_le_quantile >> operators modes. >> >> >> https://github.com/fpl/grass/commit/6b83795b037c6645a32d6a525cfdee3cc65d521c >> >> (the html file is still not updated) >> >> I'm not persuaded this is the most elegant way of doing this kind of >> things, >> maybe it would be better using an option (as in the case of -w for >> weighted >> operations) to compute average and possibly other statistics. Even, one >> could >> think in general to other multiple ways of selecting population on the >> base of >> quantiles/percentiles of population in a window. >> >> Any hint/opinion/alternative/critic about that? >> >> All this in the remote hypothesis that a pull request could have sense >> for such a kind of features. >> >> Thanks >> >> >> -- >> Francesco P. Lovergine >> _______________________________________________ >> grass-dev mailing list >> grass-dev@lists.osgeo.org >> https://lists.osgeo.org/mailman/listinfo/grass-dev >> > _______________________________________________ > grass-dev mailing list > grass-dev@lists.osgeo.org > https://lists.osgeo.org/mailman/listinfo/grass-dev >
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