(cc-ing @MarkusMetz) Yasser Said Lopez de Olmos Reyes wrote:
> > How could I obtain the differences between central pixel values and > > cardinal directions pixel values related with a central pixel? > > Or in a different manner, how to do this in grass gis? > > RASTER_OUT= round(abs((RASTER_IN - RASTER_IN_PUSHED_ONE_ROW_UP) + > > (RASTER_IN - RASTER_IN_PUSHED_ONE_ROW_DOWN) + (RASTER_IN - > > RASTER_IN_PUSHED_ONE_COLUMN_LEFT) + (RASTER_IN - > > RASTER_IN_PUSHED_ONE_COLUMN_RIGHT)) Nikos Alexandris wrote: > This boils down to calculating > (RASTER_IN - RASTER_IN_PUSHED_ONE_ROW_UP) + > (RASTER_IN - RASTER_IN_PUSHED_ONE_ROW_DOWN) + > (RASTER_IN - RASTER_IN_PUSHED_ONE_COLUMN_LEFT) + > (RASTER_IN - RASTER_IN_PUSHED_ONE_COLUMN_RIGHT) > > Please check the manual of r.mapcalc. There is > > --%<--- > THE NEIGHBORHOOD MODIFIER .. > --->%-- > which I think can be used to obtain what is asked. > So, for each of the off-current pixel, the modifiers would be like > RASTER_IN_PUSHED_ONE_ROW_UP: map[-1,0] > RASTER_IN_PUSHED_ONE_ROW_DOWN: map[1,0] > RASTER_IN_PUSHED_ONE_COLUMN_LEFT: map[0,-1] > RASTER_IN_PUSHED_ONE_COLUMN_RIGHT: map[0,1] > > I am not exactly sure about the implementation though. @Yasser, if you implement this and think it is something that can be justified as generically useful, why not ask @MarkusMetz if it is easy to include in "r.neighbors" as yet another method? Best, Nikos _______________________________________________ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user