[GRASS-dev] ​GSoC 2018 report week 01 - GRASS GIS module for Sentinel-2 cloud and shadow detection

[Stefan Blumentrath]

Ciao Roberta,

Thanks for the comprehensive report!

One general hint: Even if the drawback is complex expression(s) I would suggest merging r.mapcalc calls. That can improve performance quite a bit (less data read and written) and reduces the need to manage temporary data.

See also: https://grass.osgeo.org/<https://grass.osgeo.org/grass74/manuals/r.mapcalc.html#multiple-computations>grass74<https://grass.osgeo.org/grass74/manuals/r.mapcalc.html#multiple-computations>/manuals/r.mapcalc.html#multiple-computations<https://grass.osgeo.org/grass74/manuals/r.mapcalc.html#multiple-computations>

If you don't need the first_... To fifth_... files later, I would even say everything in 3rd_procedure.py until r.to.vect could be solved in a single mapcalc operation...

Kind regards and again thank for your GSoC work,
Stefan


________________________________
From: grass-dev <grass-dev-bounces at lists.osgeo.org> on behalf of Roberta Fagandini <robifagandini at gmail.com>
Sent: Sunday, May 20, 2018 4:33:57 PM
To: soc at lists.osgeo.org; GRASS developers list
Subject: [GRASS-dev] ​GSoC 2018 report week 01 - GRASS GIS module for Sentinel-2 cloud and shadow detection

Hi all!
I'm Roberta Fagandini and I'm working on my GSoC project, a GRASS GIS module for Sentinel-2 cloud and shadow detection.
This is my report for the first week of coding.
Since my progress has been a bit faster than expected I have already discussed with my mentors about further additions to the project. Therefore I have already updated my wiki page [0] changing the timeline. In this way, I will be able to release a more complete module.

1) What did I complete this week?

  *   Checked the prototype version of the algorithm for cloud and shadow detection
  *   Tested it
  *   I better studied the documentation of the GRASS Python Scripting Library and started coding the GRASS python script following the workflow schema prepared during the bonding period [1]
  *   Coded the 'data preparation' phase
  *   Coded the clouds detection procedure
  *   Added this first part of python script to my GitHub repository [2]
  *   Discussed with my mentors about further additions
  *   Discussed with the community about testing phase. I received some feedback and some developers stepped forward to help me in testing the algorithm
  *   Shared progress with the community

Unfortunately, I wasn't able to code on Thursday because of a PhD meeting with my supervisor.

2) What am I going to achieve for next week?

  *   Finish the translation of the algorithm in a basic python script adding the shadows detection procedure and the steps for checking and cleaning the final outputs (see [1] for details)
  *   Improve the python script so as to have a "light" working python script (manage temporary file, clean up the code, etc.)
  *   Test it and fix bugs
  *   Start implementing the GUI

3) Is there any blocking issue?
No at the moment.

Best wishes,
Roberta

[0] https://trac.osgeo.org/grass/wiki/GSoC/2018/CloudsAndShadowsDetection
[1] https://drive.google.com/file/d/1KYEKvNBurBFHw1xUTLjM0PW80Z-7br81/view?usp=sharing
[2] https://github.com/RobiFag/GRASS_clouds_and_shadows
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