Kristof Van Tricht (à Tous): 14:44: which tool is used to calculate the coherence? How computationally "heavy" is it?
Cosmin UDROIU (CS ROMANIA) (à Tous): 14:46: The S1 preprocessor is using SNAP to compute the backscatter and coherence products. 
Christina Karakizi (à Tous): 14:48: for training, which are the criteria to mark a parcel as optimal?
Laurențiu Nicola (CS ROMANIA) (à Tous): 14:49: @Christina you can't manually mark a parcel as optimal, but the main criterion is size (large parcels will be selected for training).
Christina Karakizi (à Tous): 14:51: @Laurentiu Thanks
Rubén Trenado Ordóñez (à Tous): 14:54: For grassland in mediterranean countries , where there is no mowing, there is something to deal with it?
cprietzsch (à Tous): 14:54: this is Corinna. I had to switch computers for better sound.
Cosmin UDROIU (CS ROMANIA) (à Tous): 14:55: @Kristof The S1 pre-processing is a little bit computational heavy and depends on the configuration you use (you can configure how many products to be processed in parallel). Typically, if only one product is processed at a a moment of time, a machine with 4 virtual processors and 8 or better 16 GB RAM would be required. 
Kristof Van Tricht (à Tous): 14:56: thanks!
cprietzsch (à Tous): 14:57: for S1 there is usually a threshold of 1 ha
Rubén Trenado Ordóñez (à Tous): 14:58: Thanks!
Anders Munck (à Tous): 14:58: @cprietzsch: Is that threshold configurable? If I want to set it to 0,5 ha for example.
cprietzsch (à Tous): 14:59: no this is just based on experience and analysis outside of the system shown here 
Matthias Wiegand (à Tous): 15:00: Crop type map processor: is it only applicable for PAs ( because of data access restrictions  to farmer field information)? 
Thanks
Sophie (à Tous): 15:00: The thresholds put in Sen4CAP is that a parcel must include at least 1 S1 pixel and 3 S2 pixels. 
Pieter Roggemans (à Tous): 15:00: The thresshold of 1 ha, I suppose it is only for selecting the parcels that are being trained on, so parcels < 1ha do get a prediction?
Sophie (à Tous): 15:01: Then, the system provides all results with quality flags at parcel-level, and 2 of these quality flags is the number of pixels. You can then interpret the reliability of the results using this information. 
Sophie (à Tous): 15:01: We don't put a threshold of 1ha. Only the number of pixels: 1 for S1 and 3 for S2
Sophie (à Tous): 15:02: @Matthias: no everybody can use the system. But the system is working by object. You need to provide objects to run the processor - this is the only constraint
Laurențiu Nicola (CS ROMANIA) (à Tous): 15:02: @Pieter Parcels smaller than that are not assessed, parcels with at least 10 S2 pixels are considered "best" for training.
Laurențiu Nicola (CS ROMANIA) (à Tous): 15:04: For S1 we use 20m/px pixels, and for both sensors we apply a half-pixel erosion filter
Laurențiu Nicola (CS ROMANIA) (à Tous): 15:04: Rather, a half-pixel negative buffer
Sophie (à Tous): 15:05: Rules to define the calibration dataset: 1) only crop types that have at least 30 parcels in the AOI; 2) only parcels that have more than 10 S2 pixels 
Laurențiu Nicola (CS ROMANIA) (à Tous): 15:05: But the thresholds can be configured
Pieter Roggemans (à Tous): 15:05: ok, crystal clear, thanks!
Anders Munck (à Tous): 15:06: Thanx!
Pieter Roggemans (à Tous): 15:07: Is the limitation still in place that parcels cannot overlap to treat them?
Paolo Varone (à Tous): 15:07: How do algorithms behave in case of mountain or hill surveys? For example the grassland mowing detection?
Laurențiu Nicola (CS ROMANIA) (à Tous): 15:08: @Pieter overlapping parcels are not assessed
Pieter Roggemans (à Tous): 15:08: Are there plans to remove this limitation?
Sophie (à Tous): 15:10: @Pieter: I think it is assessed, but the output of this assessment is not used to discard parcels. It is provided as a quality flag for users to interpret the results
PEREZ RUIZ Alvaro (à Tous): 15:11: The LPIS used for the AOI must have an unique id for each parcel? 
Laurențiu Nicola (CS ROMANIA) (à Tous): 15:11: @Alvaro yes, there needs to be a unique column or combination of columns that identifies the parcel
Angela Trischak (à Tous): 15:12: what do you mean with stratify in the crop type map?
Laurențiu Nicola (CS ROMANIA) (à Tous): 15:13: @Angela the idea is to split a larger site into multiple strata and do the classification for each strata independently.
Angela Trischak (à Tous): 15:14: how can i split my site?
Laurențiu Nicola (CS ROMANIA) (à Tous): 15:14: It helps if the growing seasons are too different, but each strata will have less training data, so there's a trade-off
Laurențiu Nicola (CS ROMANIA) (à Tous): 15:15: The process is a bit manual right now, but in the future you'll be able to define a shapefile with the strata boundaries, and it will be used automatically
Angela Trischak (à Tous): 15:16: therefor should I create different sites?
Sophie (à Tous): 15:16: @Paolo: relief has indeed an impact of the performance of S1 detection algorithm. Yet, the grassland mowing detection algo runs for S1 and S2 separately and you can adjust the rules when fusing the results (give more weight/confidence to S2)
Laurențiu Nicola (CS ROMANIA) (à Tous): 15:16: That also works
Laurențiu Nicola (CS ROMANIA) (à Tous): 15:18: @Pieter There's one technical reason for that limitation: we build rasters with the parcel identifiers and use them during feature extraction. Since these rasters can only represent one parcel for each pixel, in the case of overlaps, the pixels in the intersection will be assigned to only one, arbitrary parcel.
CsD (à Tous): 15:17: "Stratum" is meant an agro-ecological regoins, where we pretend (based on apriori informations) that a crops "behaves" on a simialr way, thus the same main parameters can be set for it. 
Paolo Varone (à Tous): 15:18: @Sophie: Did you run any tests in mountain?
Laurențiu Nicola (CS ROMANIA) (à Tous): 15:19: @Pieter We could include them in the crop type classification output, but the results wouldn't really be trustworthy both because of the limitation described above, and also because the input data is likely incorrect. 
davorin (à Tous): 15:19: How we can 
Stefan Erasmi (à Tous): 15:20: Can I also use my own parcels that I created from segmentation and classification of S1/S2? In Germany, LPIS data are not publicly available...
Sophie (à Tous): 15:21: @Paolo: not really - there are some mountain regions in Romania (which is one of our pilot country), but I don't know if there is a lot of grassland monitored there - need to check if you are interested
Laurențiu Nicola (CS ROMANIA) (à Tous): 15:22: @Stefan the crop type map is a supervised classification algorithm, so the parcels need to be labelled with their (expected) crop type
Paolo Varone (à Tous): 15:25: This might interest me, for Piedmont region. Any tests on pastures use?
Pieter Roggemans (à Tous): 15:25: In our PA overlapping parcels are "normal" for two reasons...
Pieter Roggemans (à Tous): 15:26: wrong declarations till they are fixed, but this is not super common. The main reason is that one farmer can declare the parcel for a certain period, then another farmer can declare it for another period in the year, but possibly this is quite specific in Flanders
Christina Karakizi (à Tous): 15:26: Can we define specific orbit's for download? For example some tiles contain values for the whole image in some orbits while in others, they contain only for half or less of the image, what do you do with that?
Laurențiu Nicola (CS ROMANIA) (à Tous): 15:26: @Pieter in the second case, are there two parcels with identical geometry and different crop codes?
cprietzsch (à Tous): 15:27: Which DEM data is used to process radiometrically calibrated S1 amplitudes?
Pieter Roggemans (à Tous): 15:28: typically the geometry will at least be very similar, the main crop code will be (should be) the same
Pieter Roggemans (à Tous): 15:29: in some cases the geometry will differ, if another farmer only uses half the parcel par example, or only applies a specific treatment on half the parcel after the main crop par example...
Diane Heymans (à Tous): 15:30: Yes this using all the images that are intersecting your AOI 
Laurențiu Nicola (CS ROMANIA) (à Tous): 15:31: @Pieter the main problem here is that it will fail our "pixel count" check (because of the label rasterization step I mentioned)
Laurențiu Nicola (CS ROMANIA) (à Tous): 15:31: @Christina you can filter the tiles to download (for S2) and orbits (for S1). But no data pixels are generally ignored.
Pieter Roggemans (à Tous): 15:32: Yes, I understand. I suppose the modularity isn't that far-reaching that I could drop in my own (python-based) image-data-extraction procedure?
Nils Fernquist (à Tous): 15:32: Can the L4B Parameters be adjusted depending on period of observation?
Laurențiu Nicola (CS ROMANIA) (à Tous): 15:32: @Corinna I think we use what SNAP supports (SRTM, not sure about the resolution)
cprietzsch (à Tous): 15:33: 30 or 90 meter DEM?
Laurențiu Nicola (CS ROMANIA) (à Tous): 15:34: @Pieter it might be easier to reset the overlap flag after importing the declarations. If two parcels have identical geometry, only one of them will be assessed, but maybe that still works for you?
cprietzsch (à Tous): 15:34: Copernicus DEM?
cprietzsch (à Tous): 15:34: thanks
Christina Karakizi (à Tous): 15:34: 
@Laurentiu, so you still use ''half'' S2 images only for pixels that do contain spectral values and not only ''whole'' cover aquistions
Pieter Roggemans (à Tous): 15:35: For identical parcels this should indeed work...
Laurențiu Nicola (CS ROMANIA) (à Tous): 15:35: @Christina yes, they're gap-filled, similarly to clouds
Laurențiu Nicola (CS ROMANIA) (à Tous): 15:36: @Pieter it works even if they're not identical, but if the overlap is large, only one parcel will be assessed. If not, both of them will be.
Pieter Roggemans (à Tous): 15:36: ok
Pieter Roggemans (à Tous): 15:38: but because each pixel is attributed to only one parcel, only part of the pixels will be used for those parcels I suppose...
Laurențiu Nicola (CS ROMANIA) (à Tous): 15:41: @Pieter what happens is that one of the parcels will be "above" the other, and "steal" its pixels. Since the pixels are the same anyway, it might not matter: the parcel that wins is assessed, the one that loses is not. But you can also have two 100 pixel parcels that have 50 pixels in common. The system would them use 100 pixels for one and 50 for the other.
Pieter Roggemans (à Tous): 15:41: clear!
CsD (à Tous): 15:55: Can we see the specifications being under preparation? 
cprietzsch (à Tous): 15:55: Thanks for the presentation. Excellent!
ion (à Tous): 15:56:  Can someone add its own markers and processor in the system?
Laurențiu Nicola (CS ROMANIA) (à Tous): 15:58: @Ion technically yes, but it might be a little hard.
Jose Sevillano (SCAYLE) (à Tous): 15:59: Is there a test set of data to try our installations? Thanks
Sophie (à Tous): 16:00: @Jose: this is something we will be preparing - this was already asked and this is indeed a good idea. Thanks