Correct me if I am wrong, but the calibration procedure is done before calculating TOA reflectances. I do not think you need to apply those factors to the L1C product.
thank you so much. I am not sure it is right or not.
But my supervisor ask me to do vicarious calibration. and also Nima Pahlevan’s paper also did it. so why I try to do it. any way, thanks a lot.
@Jan Is this calibration necessary or advisable?
In the Pahlevan’s paper they do a vicarious calibration to the L2 data (Rrs), and you are trying to apply factors to the L1C (TOA reflectances).
yes you are right. here is the other one for L1C (TOA reflectances) calibration.
the other atmospheric correction like (seaDAS polymer acolite), they could setup the vrcarious calibration. so did SNAP has any setup? or use “BandMath”? thanks
II’m sorry @marpet - I didn’t see your request.
Vicarious calibration of Sentinel-2 is undertaken as part of the monitoring activities of the Mission. It is carried out by ESL (Expert Support Labs) that report every week to ESA on the status of the instrument. The radiometric calibration of the instruments is undertaken monthly, and lead to the release of updated Absolute Calibration and On Ground Equalisation GIPPs that are assimilated into PDGS processing every month (we will be releasing the April GIPPs shortly, for entry into production on Tuesday morning).
Thus, the instruments are already calibrated prior to production of data.
More on the calibration of the instrument can be found here https://sentinels.copernicus.eu/web/sentinel/technical-guides/sentinel-2-msi/calibration and the status of the Cal/Val is reported in the Sentinel-2 L1C Data Quality Report
S2 MPC Operations Manager
Thanks @Jan. That’s what I had in mind, but wasn’t sure.
is that means I should not calibration again with Nima’s paper or 2020 report? is that right? thanks
Yes, you do not need to calibrate the data, because they are regularly calibrated.
our cluster changed. so now we use the SLURM workload manager. The code run very well ago. but now it get the error, detail below. Could you give me a hand? thanks
This sounds like the process does not have write privileges to
But I don’t know your system and can’t tell you what’s wrong.
Maybe @oana_hogoiu has an idea what could be wrong.
From the logs you povided it seems that /home/bjiang/.snap is read-only, and this is causing several crashes:
SEVERE: org.esa.snap.core.gpf.operators.tooladapter.ToolAdapterIO: /home/bjiang/.snap/auxdata/tool-adapters: Read-only file system
SEVERE: org.esa.snap.core.gpf.operators.tooladapter.ToolAdapterIO: Cannot create user folder for external tool adapter extensions
SEVERE: org.esa.snap.core.gpf.operators.tooladapter.ToolAdapterIO: Failed to scan /home/bjiang/.snap/auxdata/tool-adapters [reason: /home/bjiang/.snap/auxdata/tool-adapters]
SEVERE: org.esa.snap.lib.openjpeg.activator.OpenJPEGInstaller: OpenJPEG configuration error: failed to create /home/bjiang/.snap/auxdata/openjpeg/8.0.0
SEVERE: org.esa.snap.dataio.netcdf.NetCdfActivator: Native libraries for NetCDF could not be extracted to/home/bjiang/.snap/auxdata/netcdf_natives/8.0.0
org.h2.message.DbException: Log file error: “/home/bjiang/.snap/product-library/products.trace.db”, cause: “org.h2.message.DbException: Error while creating file “”/home/bjiang/.snap/product-library”" [90062-197]" [90034-197]
Are you running SNAP using sudo?
when i install “SNAP” software, the error :“an instance of the program cannot access specified user directory. This is a serious problem that prevent the program to function properly. make sure home/bjiang/.snap/system is writable. click ok to continue in spite of previous error”. thanks. it looks like not install successful. Could you help me ?
i try sudo, but i am not sudoer. what should i do next? thanks
[bjiang@katahdin bin]$ sudo ./snap
[sudo] password for bjiang:
bjiang is not in the sudoers file. This incident will be reported.
In the other thread you said you are sudoer.
Maybe you talk to your system administrator. Maybe they can correct the write permission for the directory.
actually, i am not sudo. But when i ask for my system administrator. They can not work any more.
my system administrator said it is not the permission issue. In the cephfs filesystem, “.snap” is special directory. Could i change the directory “./snap” when i install SNAP software? thanks
the detail below
As I’ve explained before, it’s not really a permission issue, you just can’t use the .snap directory. That’s why I suggested asking the developers how to use a different directory. Often when installing software, there are configuration options that can be tweaked. In the cephfs filesystem, .snap is a special directory and I don’t know of a way to let you use it in that way."
Ah, know I understand. I didn’t expect that you use a special file system which uses ‘.snap’ as a special directory.
CephFS Snapshots — Ceph Documentation
It is possible to change the directory used by SNAP.
You need to change two files. Both are located in
snap.properties you need to change the property
For example to:
Don’t forget to remove the ‘#’ at the beginning of the line.
snap.conf needs to be changed too.
Afterwards it should work.
thanks a lot.