[GRASS-user] largest number of consecutive days where rainfall >1 mm

[Veronica Andreo]

Hi Ivan,

It does indeed count consecutive days meeting a condition per week. That's
what the [-1] means in the t.rast.algebra command, i.e., it is the temporal
neighbourhood modifier. If you then want to get the largest weekly
consecutive days meeting the condition within a month you can aggregate the
"weekly_consecutive" time series with t.rast.aggregate granularity="1
month" method="maximum"

HTH,
Vero

El jue, 18 ago 2022 a las 14:42, Ivan Marchesini (<ivan.marchesini at gmail.com>)
escribió:

> Hi Markus
>
> thank you
>
> Yes I saw that algorithm but, if I'm not wrong, it does not fit with my
> needs. The calculation made returns the number of days, in a given
> interval (here week), that meets a certain condition. Not sure they are
> consecutive. As an example: if negative temperature occur in monday and
> thuesday and then in friday, saturday and sunday then the code count 5
> for that week. In my opinion what we need is 3.
>
> I hope I was enough clear
>
> In any case it would be good to find a solution for this type of problem
> because these type of indexes are  used for climate data analysis (e.g.:
> https://www.ecad.eu/download/millennium/millennium.php
> https://www.climdex.org/learn/indices/ )
>
> thank you
>
> Ivan
>
>
>
> On 17/08/22 20:04, Markus Neteler wrote:
> > Hi Ivan,
> >
> > On Wed, Aug 17, 2022 at 9:07 AM Ivan Marchesini
> > <ivan.marchesini at gmail.com> wrote:
> >> Dear grass user
> >>
> >> I have daily rainfall strds
> >>
> >> I would like to obtain a layer of the largest number of consecutive days
> >> where rainfall >1 mm
> > May this script code help?
> >
> https://grasswiki.osgeo.org/wiki/Temporal_data_processing#How_to_count_consecutive_days_that_meet_a_certain_condition
> ?
> >
> > Markus
> >
> >> Do you have any suggestions on how to calculate this climate index using
> >> grass's time modules?
> >>
> >> thank you very much
> >>
> >> Ivan
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