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<p>Dear Veronica</p>
<p>thank you for your answer</p>
<p>I understand your point but I still believe that the code is not
working properly for my aims</p>
<p>I try to explain myself with an example.</p>
<p>According to the example in the tutorial: <br>
</p>
<p>the first command creates a weekly mask based on my data (daily
precipitation in 2021):<br>
</p>
<p>t.rast.aggregate input=test2021 output=weekly_mask
basename=mask_week granularity="1 week" method=count nprocs=10</p>
<p>The second command add to the weekly value (7) the value of the
consecutive days in the week period<br>
</p>
<p>t.rast.algebra base=test_rr_maggiore_1mm
expression="test_consecutive_days_rr_maggiore_1mm = weekly_mask
{+,contains,l} if(test2021 < 1 && test2021[-1] < 1
|| test2021[1] < 1 && test2021 < 1, 1, 0)" nprocs=10<br>
</p>
<p>In the attached file <br>
</p>
<p><a class="moz-txt-link-freetext" href="https://drive.google.com/file/d/1eusufL8JLysac0wLfWC6oub0IM79e-KO/view?usp=sharing">https://drive.google.com/file/d/1eusufL8JLysac0wLfWC6oub0IM79e-KO/view?usp=sharing</a><br>
</p>
<p>I show an extract of the the values of a given pixel in the study
area. <br>
</p>
<p>In the first week the value of the map
"test_consecutive_days_rr_maggiore_1mm is 10 (7 + 3). 7 is the
weekly base. 3 is the number of times in which a rainy day is
preceded [-1] or followed [+1] by another rainy day. This happen
in 2021-01-05, 2021-01-09, 2021-01-10 (in fact 3 days).<br>
</p>
<p>What is not fitting my needs here is the fact that between the
2021-01-05 and 2021-01-09 there are other days without rainfall.
Actually we have not 3 consecutive days in this week!! We have 2
consecutive days: 2021-01-09, 2021-01-10 and another rainfall day
at the start of the week.</p>
<p>I would like to have, in this first week, the value of 9 (7+2)
not 10 (7+3), because I'm interested in the annual maximum length
of wet spell, in days.</p>
<p>I hope I was able to explain myself</p>
<p>Thank you again</p>
<p>Ivan<br>
</p>
<p><br>
</p>
<p><br>
</p>
<p><br>
</p>
<p><br>
</p>
<p><br>
</p>
<p><br>
</p>
<p><br>
</p>
<p><br>
</p>
<div class="moz-cite-prefix">On 18/08/22 15:36, Veronica Andreo
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CAAMki4G1AKRbf_cnuZX6Ht2nweWOW5p+5ONnhVY3DGfFd+hNMg@mail.gmail.com">
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<div dir="ltr">
<div>Hi Ivan, <br>
</div>
<div><br>
</div>
<div>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"</div>
<div><br>
</div>
<div>HTH, <br>
</div>
<div>Vero<br>
</div>
</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">El jue, 18 ago 2022 a las
14:42, Ivan Marchesini (<<a
href="mailto:ivan.marchesini@gmail.com"
moz-do-not-send="true" class="moz-txt-link-freetext">ivan.marchesini@gmail.com</a>>)
escribió:<br>
</div>
<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Hi
Markus<br>
<br>
thank you<br>
<br>
Yes I saw that algorithm but, if I'm not wrong, it does not
fit with my <br>
needs. The calculation made returns the number of days, in a
given <br>
interval (here week), that meets a certain condition. Not sure
they are <br>
consecutive. As an example: if negative temperature occur in
monday and <br>
thuesday and then in friday, saturday and sunday then the code
count 5 <br>
for that week. In my opinion what we need is 3.<br>
<br>
I hope I was enough clear<br>
<br>
In any case it would be good to find a solution for this type
of problem <br>
because these type of indexes are used for climate data
analysis (e.g.: <br>
<a
href="https://www.ecad.eu/download/millennium/millennium.php"
rel="noreferrer" target="_blank" moz-do-not-send="true"
class="moz-txt-link-freetext">https://www.ecad.eu/download/millennium/millennium.php</a>
<br>
<a href="https://www.climdex.org/learn/indices/"
rel="noreferrer" target="_blank" moz-do-not-send="true"
class="moz-txt-link-freetext">https://www.climdex.org/learn/indices/</a>
)<br>
<br>
thank you<br>
<br>
Ivan<br>
<br>
<br>
<br>
On 17/08/22 20:04, Markus Neteler wrote:<br>
> Hi Ivan,<br>
><br>
> On Wed, Aug 17, 2022 at 9:07 AM Ivan Marchesini<br>
> <<a href="mailto:ivan.marchesini@gmail.com"
target="_blank" moz-do-not-send="true"
class="moz-txt-link-freetext">ivan.marchesini@gmail.com</a>>
wrote:<br>
>> Dear grass user<br>
>><br>
>> I have daily rainfall strds<br>
>><br>
>> I would like to obtain a layer of the largest number
of consecutive days<br>
>> where rainfall >1 mm<br>
> May this script code help?<br>
> <a
href="https://grasswiki.osgeo.org/wiki/Temporal_data_processing#How_to_count_consecutive_days_that_meet_a_certain_condition"
rel="noreferrer" target="_blank" moz-do-not-send="true"
class="moz-txt-link-freetext">https://grasswiki.osgeo.org/wiki/Temporal_data_processing#How_to_count_consecutive_days_that_meet_a_certain_condition</a>?<br>
><br>
> Markus<br>
><br>
>> Do you have any suggestions on how to calculate this
climate index using<br>
>> grass's time modules?<br>
>><br>
>> thank you very much<br>
>><br>
>> Ivan<br>
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</blockquote>
</div>
</blockquote>
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