I’am using sen2cor standalone on a linux machine.
Unfortunately, it take quite a while to process a 7.1 GB scene.
I wonder, if I could subset my images to the actual extend of my study site and afterwards I start the sen2cor process.
So, first:
Can I correct subsetted data with sen2cor standalone?
second:
Is anyone knowing an elegant way to subset the S2 images in its raw data format?
I would prefer to do that with python or better in the command line in the linux terminal.
I don’t want to do it manually in Snap.
Hi, you can not apply sen2co to a subset of a S2 data product. This because sen2cor can only work with S2 data organized in the .SAFE format , while a S2 subset can be saved for example in a .DIM format but it is not possible yet to save a subset with the original S2 format. What you can do is only to process the full S2 product with sen2cor and only after that you can define your subset with atmospheric correction.
Yes it is quite time consuming…but it is the only way at the moment. These shoul be the steps :
download the dataset
sen2cor processing
resampling the level2 dataset to 10m
subsetting and export
By the way , if you are working on dataset of europe you can surely download the Level2 product directly instead of the L1C product, it depends on the date of the acquisition. When had the data been acquired ?
Actually I want to download the entire time series which is available for my test sites in North-Eastern of Germany (so, europe).
-> Downloading, pre-processing, checking cloud coverage, applying fancy methods
As far as I know or checked, the Level2 data are only available for a few randomly chosen images?!
Sentinel-2 L2A (BOA) are systematically generated over Europe since April 2017 and available on SciHub, therefore if you need S2 data acquired before that date over Europe you need to run Sen2Cor.
My search of S2A and S2B data on scihub.copernicus.eu showed the following results:
Period: 2015 - Today
Study Site:a part of North-Eastern Germany
S2A_L1C | 1047 images | first image 2016-08-09
S2A_L2A | 470 images | first image 2017-04-10
S2B_L1C | 366 images | first image 2017-07-01
S2b_L2A | 73 images | first image 2017-12-18
My Questions:
So, since April 2017 we have 470 available images in L2A for S2A. Does it means, that we have 1047-470 = 577 images available before April 2017 (in L1C)?
Why there are no corrected images (S2B_L2A) between July and December 2017? Is the preprocessing worklow considering something like cloud coverage and it eliminates images with 100 % coverage? Or is there also another explanation?
Would be aweful, if we don’t have no images at all between July and December 2017.
Q1. So, since April 2017 we have 470 available images in L2A for S2A. Does it means, that we have 1047-470 = 577 images available before April 2017 (in L1C)? A1. Yes, you are right, but pay attention because some S2 data could be replicated due to the re-processing when a new baseline was released, if you have more than one S2 tile acquired on the same day I would suggest to use the ones with the most recent processing date.
Q2. Why there are no corrected images (S2B_L2A) between July and December 2017? Is the preprocessing worklow considering something like cloud coverage and it eliminates images with 100 % coverage? Or is there also another explanation? A2. You do not find S2B_L2A between July and December 2017 because the systematic processing of S2B_L1C to BOA started in December 2017 after the commissioning phase.
Sorry, but I need to understand the selection of available L2A data.
I downloaded all available data from January 2018 for my study site, both L1C and L2A.
I got much more data in L1C and not only more images but also from different dates.
In the image I selcted dates in red, where there are a lot of data in L1C but no data in L2A.
Cloud coverage can’t be the resaon, because in January we don’t have one single image at all without cloud coverage.
So, why the red selected images are not available in L2A?
What is your AOI? As identified here Level-2A products are systematically generated at the ground segment over Europe, but the production will be extended to global by the end of 2018.
