[GRASS-user] r.sun.daily ouputs

[Anna Petrášová]

Hi,

On Sep 29, 2017 3:16 AM, <balotti.and at gmail.com> wrote:

Hi Anna,
Here the test on NC dataset, I reduced a little bit the resolution to
speedup computation:

   1. g.region raster=elevation res=30 -p
   2. r.resamp.interp input=elevation at PERMANENT output=dem30
   3. r.slope.aspect elevation=dem30 at PERMANENT slope=slo aspect=asp
   4. r.sun.daily -t elevation=dem30 at PERMANENT aspect=asp at PERMANENT
   slope=slo at PERMANENT start_day=91 end_day=304 glob_rad=sol_glob
   glob_rad_basename=sol nprocs=4
   5. t.rast.series input=sol at PERMANENT method=sum output=sol_sum

And the output querying on a random pixel is:

est, nord: 636522.196262, 219573.598131
sol_glob at PERMANENT: value: 28270.75
sol_sum at PERMANENT: value: 1632588.35400391

The only thing that could create problem maybe is that during the execution
of r.sun.daily I received many warnings like this (translated: can't rename
file NULL/CELL)

WARNING: Non riesco a rinominare il file null 'C:\...\GRASS_data\nc_basic_
spm_grass7\PERMANENT\.tmp/unknown\4860.1' in 'C:\...\GRASS_data\nc_basic_
spm_grass7\PERMANENT\cell_misc\sol_glob\null': File exists
WARNING: Non riesco a rinominare il file cella 'C:\...\GRASS_data\nc_basic_
spm_grass7\PERMANENT\.tmp/unknown\4860.0' in 'C:\...\GRASS_data\nc_basic_
spm_grass7\PERMANENT\fcell\sol_glob': File exists

Since sum by r.sun.daily is less than sum by t.rast.series, maybe the
summed file is not properly summed and represent just the sum of the last
days of the period?
P.S. I am on Windows with GRASS 7.2.1


That is helpful, thanks, I think I know what might be wrong looking at the
code. It apparently works on Linux, but not on Windows. I don't have time
today, but will fix it as soon as possible. Thank you!

Anna

---
Andrea Balotti

Il 28/09/2017 19:00, Anna Petrášová ha scritto:

Hi,


On Thu, Sep 28, 2017 at 5:30 AM,  <balotti.and at gmail.com>
<balotti.and at gmail.com> wrote:

Hi,
I am using  r.sun.daily to perform global radiation maps over a range of
dates but I am a little bit confused about the outputs of this module.
I created two outputs: the accumulated map of the whole time period and a
temporal dataset with all the daily maps.
I have tried to aggregate the daily maps in the temporal dataset with
t.rast.series (average and sum) supposing that one of them was the same with
the accumulated output of r.sun.daily but I was wrong.
Here the query on a pixel: the first line is the accumulated map from
r.sun.daily, the last two line are the aggregated maps from t.rast.series.
sol_glob_veg at PERMANENT: value: 24291.95
sol_veg_sum at PERMANENT: value: 1495683.87133789
sol_veg_avg at PERMANENT: value: 6989.17696886865 <(769)%20688-6865>

My question now is which kind of accumulation perform r.sun.daily?
TIA

it just sums the maps from each day, so t.rast.series with sum should
give you the same results. I tested it in NC sample datatset and
indeed it gave me identical results. Could you test it in the sample
dataset and perhaps send the commands you are using?

Thank you,

Anna


--
Andrea Balotti


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