Hi Hamish, On Sun, Oct 10, 2010 at 8:42 AM, Hamish <[email protected]> wrote: > Hi, I was trying to figure out how to use the r.series threshold= > parameter to make a MASK only where all channels of some Landsat > data were >0 (extant),
Perhaps use the count parameter with -n for null propagation? > without needing to use r.null and the extra disk > space to store a NULL file for each of the input bands (the files take up > enough disk space as it is). so something like "output cells contain the > count of input maps with data values >=1". for 6 input bands the output > range would be 0-6, or null and 1-6. So the sum parameter sounds better. > ... but I was having a difficult time of understanding how it was > supposed to work. the only mention in the man page has to do with the > range= option. > > Remembering there was some discussion about it I just found this: > http://article.gmane.org/gmane.comp.gis.grass.devel/22002/ > > .. so was the html part of the patch just never applied? or did things > change since then? ie is it still true that the -n flag makes it ignored? > (perhaps then issue a G_warning()?) Time to reverse engineer the code :) > Is threshold= not even related to the method=threshold option?! Here a usage example: # Growing Degree Days maps thresholding, seeking 1350 GDD r.series in=gdd1,gdd2,gdd3,gdd4,...,gdd365 \ out=gdd_daynum.thresh1350 threshold=1350 method=threshold The output is, for eacxh pixel, the map number in which 1350 GDD have been reached. I agree that documentation could be better... Markus _______________________________________________ grass-dev mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-dev
