Theia Workshop for Sentinel-2 L2A MAJA products – 13 & 14 June 2018 Sentinel-2 for Agriculture S2 OPERATIONAL EXPLOITATION FOR SUPPORTING NATIONAL TO REGIONAL AGRICULTURE MONITORING AROUND THE WORLD AT PARCEL LEVEL Bontemps S., Defourny P., Bellemans N., Cara C., Dedieu G., Guzzonato E., Hagolle O., Inglada J., Nicola L., Rabaute T., Savinaud M., Udroiu C., Valero S., Koetz B. & 12 benchmarking & demonstration sites partners Theia Workshop for Sentinel-2 L2A MAJA products – 13 & 14 June 2018
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Theia Workshop for Sentinel-2 L2A MAJA products – 13 & 14 June 2018
Sentinel-2 for AgricultureS2 OPERATIONAL EXPLOITATION FOR SUPPORTING NATIONAL TO REGIONAL
AGRICULTURE MONITORING AROUND THE WORLD AT PARCEL LEVEL
Bontemps S., Defourny P., Bellemans N., Cara C., Dedieu G., Guzzonato E., Hagolle O., Inglada J., Nicola L., Rabaute T.,
Theia Workshop for Sentinel-2 L2A MAJA products – 13 & 14 June 2018
Thank you for your attention
… and come and play with us!http://www.esa-sen2agri.org/
Theia Workshop for Sentinel-2 L2A MAJA products – 13 & 14 June 2018
Theia Workshop for Sentinel-2 L2A MAJA products – 13 & 14 June 2018
Sen2-Agri system: S2 exploitation for local to national
operational agriculture monitoring at 10 m
Decametric time series availability allow to proceed to full scale experimenton annual basis – Sentinel-2b much needed and Sentinel-1 integration wouldclearly enhance the timeliness and the robustness
Nationwide Sen2Agri NRT operation requires good processing but more critically in situ data collected and quality controlled in a timely manner(logistics matter a lot - flooding in Sudan, unrest in Madagascar, etc.)
Very fast learning curve thanks to this challenging globally distributeddemonstration allowing to further improve the Sen2Agri system optimizingoperational performances (timeliness, accuracies in challenging landscapes)
Sen2Agri system is a turn-key system able to evolve in close partnerships with national stakeholders to insure outcome relevance and ownership -multi-year experience much needed to fully exploit Sentinel-2 capabilities !
Theia Workshop for Sentinel-2 L2A MAJA products – 13 & 14 June 2018
Sen2-Agri is free and open source
Based on open source existing software
Under GNU-GPL License
Open source software based on Orfeo ToolBox
Cluster-ready architecture for distributed processing
Integration with Sentinel-2 ToolBox
Operational system required : CentOS7 (GNU/LINUX)
Theia Workshop for Sentinel-2 L2A MAJA products – 13 & 14 June 2018
• Optional to generate the cropland mask
• Mandatory to generate the croptype map
Field campaigns for cropland and croptype can be combined.
The quality of the in situ data set is the most important driver of the quality of the output maps
With the proper format, one single dataset can be given to the system.
2 different objectives:
In situ data for calibration/training of the machine learning algorithms: sampling to cover the diversity of the existing classes accross the site. It should represent the range of possible land cover types and crop types.
In situ data for validation: to estimate the model performance to recognize the different classes. To be consider as a proper map validation, the validation dataset should be collected using a statistically-sound sampling.
In situ data collection
By-default split of the dataset:75% of the samples to support the training25% of the samples to test the performance of the classifier
Theia Workshop for Sentinel-2 L2A MAJA products – 13 & 14 June 2018
• Shapefile to be provided with specific attribute table format [cfr Software User Manual]
• Stratification should be applied in case of large area mapping
• Guidelines for field campaign method are provided by the JECAM network:http://www.jecam.org/JECAM_Guidelines_for_Field_Data_Collection_v1_0.pdf
Dedicated webinar on in situ data collection methods is planned on July 19th
Theia Workshop for Sentinel-2 L2A MAJA products – 13 & 14 June 2018
If you intend to use the Sen2-Agri system on a local site (~90 000km²), the minimum system requirements to install and run this system are as follows:
• CPU: 8 Cores
• RAM: 32GB
• HDD Storage: 4 TB
• SSD Storage: 250 GB (optionnal – for temporary files)
If you intend to use the Sen2-Agri system on a national site (~500 000km²), the minimum system requirements to install and run this system are as follows:
• CPU: 16 to 32 Cores
• RAM: 64GB to 128 GB
• HDD Storage: 10 TB is enough even if 15TB is recommended
• SSD Storage: 1 TB (optionnal – for temporary files)
System requirements
Theia Workshop for Sentinel-2 L2A MAJA products – 13 & 14 June 2018
Amount of downloaded product (L1C Sentinel-2 and L1T Landsat 8)
For the system initialization (multi-temporal atmospheric correction)
S2: 63 products, 226 GB
L8: 327 products, 621 GB
For the growing season until today
S2: 427 products – 1.341TB
L8: 623 products – 1.2TB
Amount of L2A generated
For the system initialization (multi-temporal atmospheric correction)
S2: 63 products, 756 GB (2 months)
L8: 146 products, 205 GB (3 months)
For the growing season until today
S2: 427 products – 5.33 TB
L8 : 554 products – 775 GB
High level figures :
Ukraine national demonstration
Theia Workshop for Sentinel-2 L2A MAJA products – 13 & 14 June 2018
Processing time for each Sen2Agri product
• For Atmospheric correction: Around 30 minutes per tile
• For Cloud free composite: 8 days for a product with S2 and L8
• For LAI: Approx. 3 minutes/ S2 tile
• For L4A: About 3 days for the raw mask, about 5 days and a half for segmentation
• For L4B: About 8 days
National hardware server : 2 x Intel(R) Xeon(R) CPU E5-2650 v3 @ 2.30GHz (20 cores total, 40
threads), 128 GB RAM (26 TB disk space)
System performances over national sites
Theia Workshop for Sentinel-2 L2A MAJA products – 13 & 14 June 2018
Madagascar site – mid-season cropland and
crop type products thanks to timely in situ data
Theia Workshop for Sentinel-2 L2A MAJA products – 13 & 14 June 2018
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Theia Workshop for Sentinel-2 L2A MAJA products – 13 & 14 June 2018
Madagascar site – mid-season cropland and
crop type products thanks to timely in situ data
Theia Workshop for Sentinel-2 L2A MAJA products – 13 & 14 June 2018
November 201650 days window
5/10/2016-25/11/2016
First cloud free composite series over Mali
at 10m resolution from Sentinel-2 and Landsat 8
Theia Workshop for Sentinel-2 L2A MAJA products – 13 & 14 June 2018
Cropland product for local site in Northern China
without in situ data (trained from global CCI LC map)
Cropland mask, obtained without in-situ data but using the ESA CCI Land Cover map to extract training dataset(http://maps.elie.ucl.ac.be/CCI/viewer/)
Cropland
Non cropland
Theia Workshop for Sentinel-2 L2A MAJA products – 13 & 14 June 2018
Monthly cloud-free composite
Benchmarking conclusions
• Weighted average approach
• Compositing period can vary between 30 to 50 days window
• Implements a directional correction for seamless composites
• Recurrent implementation : L3A product updated with each new L2A product
To limit the data volume to keep on-line in Sen2Agri system
April, France
Theia Workshop for Sentinel-2 L2A MAJA products – 13 & 14 June 2018
Dynamic cropland mask2 chains implemented to deal with presence/absence of in-situ data
• Linear interpolation of the refl data for the in situ data version• Based on the crop mask previously generated• Random forest classifier• Classifier applied on temporal features : surface reflectance, NDVI,