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

GRASS GRASS developer
1

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

2

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/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@lists.osgeo.org on behalf of Roberta Fagandini robifagandini@gmail.com
Sent: Sunday, May 20, 2018 4:33:57 PM
To: soc@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

3

Ciao Stefan!

···

2018-05-20 21:44 GMT+02:00 Stefan Blumentrath <Stefan.Blumentrath@nina.no>:

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/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…

Thank you so much for your hints! I’m trying to clean up the code without creating a too complex expression…I hope to share the new version by this evening or tomorrow at the latest.

Kind regards and again thank for your GSoC work,

Stefan

Thanks again!!
Roberta

From: grass-dev <grass-dev-bounces@lists.osgeo.org> on behalf of Roberta Fagandini <robifagandini@gmail.com>
Sent: Sunday, May 20, 2018 4:33:57 PM
To: soc@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