[GRASS-user] Alternative to r.median for GRASS 7.x?

[Stefan Blumentrath]

Hi Nikos,

Did you consider using r.univar (with a zones map, like v.rast.stats does: https://trac.osgeo.org/grass/browser/grass/branches/releasebranch_7_2/scripts/v.rast.stats/v.rast.stats.py#L238, just with colon as separator) and using the resulting table as input to r.recode (https://grass.osgeo.org/grass74/manuals/r.recode.html) for example?

Cheers,
Stefan


-----Original Message-----
From: grass-user [mailto:grass-user-bounces at lists.osgeo.org] On Behalf Of Nikos Alexandris
Sent: fredag 26. januar 2018 19.52
To: GRASS-GIS user mailing list <grass-user at lists.osgeo.org>
Subject: [GRASS-user] Alternative to r.median for GRASS 7.x?

Dear statistics experts,

how can we compute the median of a floating point cover raster map, over a base map (using the conventional terminology as in r.stats.zonal)?

It appears that there is no module to get the median out of floating point raster maps, using a base map as in r.stats.zonal or r.statistics (which does not support floating point figures).

Is there an alternative to r.median for GRASS 7.x?


A work around with r.statistics, is to use r.reclass and get the floating point numbers (reported via r.stats -n1) as category labels of the cover map. Yet, r.reclass rounds up floats before assigning a category.

At the moment the shortest path seems to be v.rast.stats. This would require some conversions back and forth from raster to vector for the base map though.

Thank you for any hints, Nikos