[GRASS-user] r.series weights to zero

[Frank David]

Le 09/06/2018 à 19:04, Markus Metz a écrit :
>
>
> On Fri, Jun 8, 2018 at 12:30 PM, Frank DAVID <frank.david at geophom.fr 
> <mailto:frank.david at geophom.fr>> wrote:
> >
> >
> >
> >
> > Cordialement,
> > Frank David
> >
> >
> > -------- Message d'origine --------
> > De : Markus Metz
> > Date :07/06/2018 17:30 (GMT+01:00)
> > À : Frank David
> > Cc : grass-user , GRASS developers list
> > Objet : Re: [GRASS-user] r.series weights to zero
> >
> >
> >
> > On Tue, Jun 5, 2018 at 2:51 PM, Frank David <frank.david at geophom.fr 
> <mailto:frank.david at geophom.fr>> wrote:
> > >
> > > Hi all Grass users,
> > >
> > > It's seems that r.series weights does not accept zero as weight... 
> Is it possible ?
> >
> > Yes, weights must be positive.
> >
> > > and so, why ?
> >
> > A zero weight means that all values in this map are ignored. Zero 
> weights can also cause the sum of weights to be zero, leading to 
> division by zero and finally to +inf / -inf as a result
> >
> > Thank you Markus for your reply.
> > I would think it would have been interesting to use zero as weight 
> on some raster in order to use (or not) them depending on the context. 
> For my purpose i will use a value next to zero.
>
> Agreed. The underlying functions test if the sum of weights is zero, 
> thus it is ok if at least one weight is larger than zero, otherwise 
> the result is NULL. Zero weights are now allowed in r.series, trunk 
> r72789.
>
Great !. Thank you Markus
Frank
> Markus M
>
> > Thanks again
> > Frank
> >
> >
> >
> > Markus M
> > >
> > > I've got the following error message when running r.series with 
> one weight set to 0
> > >
> > > "/usr/local/grass-7.4.0svn/etc/python/grass/script/core.py",
> > > line 332, in handle_errors
> > >     returncode=returncode)
> > > grass.exceptions.CalledModuleError: Module run None
> > >
> > > Thank you for your comment.
> > >
> > > Frank
> > >
> > >
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> >

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