[GRASS-dev] GSoC 2018 report week 10 - GRASS GIS module for Sentinel-2 cloud and shadow detection

[Roberta Fagandini]

Hi Markus!

2018-07-24 14:43 GMT+02:00 Markus Neteler <neteler at osgeo.org>:

> Hi Roberta,
>
> Roberta Fagandini <robifagandini at gmail.com> schrieb am Di., 24. Juli
> 2018, 11:38:
>
>> Hi Martin,
>> as Moritz suggested, Id like to have your opinion about the
>> implementation of a new procedure for downloading Sentinel images avoiding
>> too many dependencies.
>>
>
> I'm following loosely as I'm on the road at time but I'd like to better
> understand this discussion.
>
>
> I'm working on a module (i.sentinel.preproc [0]) which wraps the import
>> and the atmospheric correction of sentinel images. My intention is to add
>> also the download phase but I'd like to avoid dependencies. That's
>>
> the reason why I'm not using i.sentinel.download at the moment.
>>
>
> This isn't clear to me so far. The only potential dependency would be
>
> g.extension i.sentinel
>
> right? Which uses a pip installable library.
>

i.sentinel.download requires both sentinelsat and pandas (both installable
with pip).
In a previous discussion, I asked about the installation of the python
library Py6S and the dev community strongly encouraged me to avoid too many
dependencies (also Py6S requires pandas). Consequently I wrote my own
routine to read AERONET file and compute AOT at 550nm.
That's the reason why I'm trying to avoid dependencies.


>
> I found this python script [1] that maybe could solve the problem of
>> dependencies and it could be a good starting point.
>>
>
> For me that script doesn't work, tried a few days ago (while
> i.sentinel.download does work).
> What is the advantage of having the dependency [1] over an existing GRASS
> add-on?
>

I have not tested the script yet, but looking at the code I think I can try
to implement part of the code in my module changing it accordingly with the
requirements of a GRASS GIS module. This should avoid the installation of
both sentinelsat and pandas. Right?


>
> What do you think?
>>
>> As always any feedback is welcome!
>>
>
> I'd rather consider to share code with the existing addon than starting
> from scratch.
> But perhaps I'm still overlooking something.
>

Obviously, it would be easier for me to use the existing addon
(i.sentinel.download) but I struggled quite a lot to avoid pandas and other
dependencies ;-). I do not know if it makes sense to add it now in order to
integrate a module that already exists and that users can use separately.
What do you think?


Roberta



>
> My 0.02 holiday cents :)
> Markus
>
>
>> Thanks in advance.
>>
>> Roberta
>>
>> [0] https://github.com/RobiFag/GRASS_clouds_and_shadows
>> [1] https://github.com/olivierhagolle/Sentinel-download
>>
>>
>
>>
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