Earthdata Forum

Hello,
I try to use Seadas7.3 to process Landsat8 data, but got some problems.
Sometimes, I can get beautiful results (e. g. Fig1 in attached). However, for some other cases, the images seem noisy and unreasonable (e. g. Fig2 in attached).
I also checked l2_flags, as two images shown in the attachment (it is located in Quemoy island), The lands are not marked in both of the image. The value of Rrs443 in fig.1 is equal to 0 while the value in Fig.2 is larger than 0 in the continental area.
I am wonder why landmask is not overlapped in Fig.2?
Cheers,

YH

I do not quite understand this question.  If you post the l2gen par file (or full param list) of what you used when processing this it would help us determine exactly how you processed this.  Are you saying that pixels over land are not being identified as LAND in the MaskManager? 

Danny

Sorry, I made a mistake.
I changed the default value of the param 'land' in my code. It's normal right now.
Thanks for everyone.

YH

Hi, can I have two questions Im processing landsat 8 data using L2gen
1- It doest not give Rrs value in NIr band (865 nm)
2- can I process Landsat ETM+ data using L2gen?

1- It doest not give Rrs value in NIr band (865 nm)?
What do you mean?  If you mean that it doesn't generate the product Rrs_865 by default then this is correct.  The default for Rrs is Rrs_vvv which is all the visible bands and does not include Rrs_865.  You would need to specify Rrs_865 in the product list (l2prod).
2- can I process Landsat ETM+ data using L2gen?
Sorry, but no, currently l2gen only supports the OLI instrument for Landsat.

Danny

> 2- can I process Landsat ETM+ data using L2gen?
> Sorry, but no, currently l2gen only supports the OLI instrument for Landsat.

Well...it does, but it's not officially (or at least fully) supported in SeaDAS, nor has it been extensively tested...but
if you want it.... 
You would need to install the supporting data files manually.

Sean

Thank you.

Hi Sean,

I have a follow up question about the l2gen for Landsat 5 and Landsat 7.
According to your comments, I have installed the bundle of Landsat 5 tm manually, and try to process the Landsat 5 data using the default parameter, however, the it didn't work. The detail of processing was:

l2gen ifile=LT05_L1TP_119038_20110425_20161208_01_T1_MTL.txt ofile=test_l2.nc

Input file LT05_L1TP_119038_20110425_20161208_01_T1_MTL.txt is a Landsat 5 TM L1B GEOTIFF file.
Loading default parameters from /seadas/seadas-7.4/ocssw/share/common/msl12_defaults.par
Loading default parameters for L5TM from /seadas/seadas-7.4/ocssw/share/l5tm/msl12_defaults.par
Loading parameters for suite OC from /seadas/seadas-7.4/ocssw/share/l5tm/msl12_defaults_OC.par
Loading command line parameters

Loading user parameters for L5TM

Loading characteristics for L5TM
Opening sensor information file /seadas/seadas-7.4/ocssw/share/l5tm/msl12_sensor_info.dat
  Bnd   Lam       Fo    Tau_r     k_oz    k_no2    t_co2   awhite       aw      bbw
    0  485.000  198.150 1.644e-01 2.226e-02 3.070e-19 1.000e+00 1.000e+00 1.827e-02 1.487e-03
    1  569.000  179.648 8.562e-02 1.082e-01 7.613e-20 1.000e+00 1.000e+00 1.086e-01 7.616e-04
    2  660.000  153.668 4.680e-02 5.868e-02 1.107e-20 1.000e+00 1.000e+00 4.081e-01 4.096e-04
    3  840.000  103.034 1.824e-02 3.554e-03 1.756e-22 1.000e+00 1.000e+00 3.824e+00 1.547e-04
    4 1676.000   22.000 1.118e-03 0.000e+00 0.000e+00 1.000e+00 1.000e+00 7.112e+02 9.001e-06
    5 2223.000    8.344 3.643e-04 0.000e+00 0.000e+00 1.000e+00 1.000e+00 2.496e+03 2.889e-06

-E- number of qaa_wave elements must be 5.

The L5 TM only have four VIS bands, the error makes me wonder.

And for the Landsat 7 ETM, another problem occurred.
ZhigangdeMacBook-Pro:LE07_L1GT_119038_20190407_20190502_01_T2 zhigang$ l2gen ifile=LE07_L1GT_119038_20190407_20190502_01_T2_MTL.txt ofile=test.nc
Input file LE07_L1GT_119038_20190407_20190502_01_T2_MTL.txt is a Landsat 7 TM L1B GEOTIFF file.
Loading default parameters from /seadas/seadas-7.4/ocssw/share/common/msl12_defaults.par
Loading default parameters for L7ETM from /seadas/seadas-7.4/ocssw/share/l7etm/msl12_defaults.par
-E- clo_readFile: Can't open parameter file - /seadas/seadas-7.4/ocssw/share/l7etm/msl12_defaults.par

But, I can see the content of the file : cat /seadas/seadas-7.4/ocssw/share/l7etm/msl12_defaults.par, why the l2gen cannot read this file?
I have no idea how to deal with it, could you help me?

Regards,
Zhigang

Try removing the line "qaa_ave=" from $OCDATAROOT/l5tm/msl12_defaults.par

Thanks Sean. I have remove this line. Although there is another problem, the l2gen does work when I didn't generate chlora.....chl_hu: incompatible sensor wavelengths for this algorithmchl_hu: -1 1 2....I also solved the problem for l7etmp ('cannot read the msl12_defaults.par'). The command git clone https://oceandata.sci.gsfc.nasa.gov will clone the bundle into l7etmp folder automatically, however the l2gen will read the msl12_defaults.par from l7etm, only change the folder name will work.Best Regards,Zhigang