netcdf file processing

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osrani
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Joined: Mon Nov 19, 2018 10:11 am America/New_York

netcdf file processing

by osrani » Tue Dec 04, 2018 1:02 pm America/New_York

Thank you Sean. You are right .
Previous post error in seadas licence
-E- /home/seadas/ocssw/oel_hdf4/libdfutils/wrapper.c line 586: Could not create NCDF4 file, /home/itra/Data/seadas_outputs/sentinel-2_op/test_msi2.L2 .
-E- l2gen: Error opening /home/itra/Data/seadas_outputs/sentinel-2_op/test_msi2.L2 for writing.

In this the path  is taken /home/seadas/ocssw/oel_hdf4/libdfutils/wrapper.c line 586:  but the path of oel_hdf4/libdfutils/wrapper.c line 586 in my system was:
/home/itra/seadas-7.5.1/ocssw/ocssw-src/oel_hdf4/libdfutils/wrapper.c line 586.
How can I change this path, as I am not giving this path in command?

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OB.DAAC - SeanBailey
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netcdf file processing

by OB.DAAC - SeanBailey » Tue Dec 04, 2018 1:33 pm America/New_York

The error message is reporting the line in the code with the path from the machine on which it was compiled, but that is NOT the problem.
This is the file that cannot be created:
/home/itra/Data/seadas_outputs/sentinel-2_op/test_msi2.L2

which comes from the ofile option passed to l2gen.

The path /home/itra/Data/seadas_outputs/sentinel-2_op/ needs to exist and be writable by the user running l2gen.

Sean

osrani
Posts: 19
Joined: Mon Nov 19, 2018 10:11 am America/New_York

netcdf file processing

by osrani » Tue Dec 04, 2018 10:20 pm America/New_York

Thank you Sean .
Problem solved.

osrani
Posts: 19
Joined: Mon Nov 19, 2018 10:11 am America/New_York

netcdf file processing

by osrani » Wed Dec 05, 2018 12:13 am America/New_York

Hai
After processing l2gen ,I got Rrs442,492,559, 665 and 704 but I need Rrs at 443,490,670and 680 for chl extraction .
So I tried spectral response function to get weighted band Rrs.Now I unable to understood how to get Rrs at particular wavelength(required)  from this weighted band Rrs.Please suggest me to some ref to calculte RRs at particular wavelengths.

OB.DAAC - SeanBailey
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netcdf file processing

by OB.DAAC - SeanBailey » Wed Dec 05, 2018 8:58 am America/New_York

The short answer is you cannot.  There is insufficient information in the reflectances measured by the MSI instrument to generate an arbitrary set of reflectances at different band centers.
The MSI bands are also designed for land applications and have very wide band widths.
(e.g. the 492nm channel is 66nm wide!) . 
For all but the 680nm channel, you could simply use the closest band (e.g. use 442 for 443).  If the algorithm you wish to employ requires 680nm, it cannot be used for MSI.

Sean

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