Re: Alternative to r.median for GRASS 7.x?

Nikos Alexandris <[email protected]> Sun, 28 Jan 2018 01:38:38 +0100

Newsgroups	gmane.comp.gis.grass.user
Message-ID	<[email protected]>

Hi,

No!  Honestly, I did not see the "zones" parameter :-O

Reads as something worth trying.  As Anna indicated `r.stats.quantiles`,
however, looks there is a kind-of direct option.

Thank you!


* Stefan Blumentrath <[email protected]> [2018-01-26 21:43:49 +0000]:

>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:[email protected]] On Behalf Of Nikos Alexandris
>Sent: fredag 26. januar 2018 19.52
>To: GRASS-GIS user mailing list <[email protected]>
>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

-- 
Nikos Alexandris | Remote Sensing & Geomatics
GPG Key Fingerprint 6F9D4506F3CA28380974D31A9053534B693C4FB3

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