SeaDAS-MOD04

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SeaDAS-MOD04

by fjqkszcg » Fri Dec 16, 2022 6:10 am America/New_York

Using SeaDAS processing data(MOD04 and MOD11) downloaded from https://ladsweb.modaps.eosdis.nasa.gov/, MOD04 data can be imported normally, but MOD11 data import error, Now ask for help! Thanks!

The error message is as follows:
=======================================================
An exception occurred:
Type:java.util.concurrent.Exception
Message:java.NumberFormatException:For input string:"NA"
=======================================================

The data is as follows:
=======================================================
MOD04_3K.A2018069.0255.061.2018073234130.hdf
【MODIS Aerosol Optical Depth Products】
MOD11_L2.A2018069.0255.061.2021325144022.hdf
【MODIS Land Surface Temperature Products】
=======================================================
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OB SeaDAS - xuanyang02
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Re: SeaDAS-MOD04

by OB SeaDAS - xuanyang02 » Fri Dec 16, 2022 9:54 am America/New_York

In MOD11_L2.A2018069.0255.061.2021325144022.hdf, the band QC has "NA" for _FillValue, which causes the problem for SeaDAS' netCDFRerader. We fixed the bug, and hopefully it will be in the next release.

This is in the metadata --
ushort QC(Along_swath_lines_1km\:MOD_Swath_LST, Cross_swath_pixels_1km\:MOD_Swath_LST) ;
QC:long_name = "Quality control for daytime LST and emissivity" ;
QC:Number\ Type = "uint16" ;
QC:valid_range = 0US, 65535US ;
QC:_FillValue = "NA" ;


In the meantime, if you can replace "NA" with "0US" for QC's _FillValue in MOD11_L2.A2018069.0255.061.2021325144022.hdf, SeaDAS can read the modified file.

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Re: SeaDAS-MOD04

by fjqkszcg » Fri Dec 16, 2022 2:42 pm America/New_York

Thank you very much!

OB.DAAC - SeanBailey
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Re: SeaDAS-MOD04

by OB.DAAC - SeanBailey » Fri Dec 16, 2022 5:41 pm America/New_York

To be clear, the code issue was not technically a bug, rather the _FillValue defined in the MOD11 product is not appropriate when using the netCDF API to read the file. A proper netCDF file requires the fill value to be the same data type as the data set. "NA" is not an unsigned short, so the netCDF API complains (appropriately so).

The code fix is just trapping this erroneous input data condition.

Sean

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Re: SeaDAS-MOD04

by fjqkszcg » Sat Dec 17, 2022 6:33 am America/New_York

Hello!
This Bug in SeaDAS makes it impossible to process the data of MOD11(Land Surface Temperature) at present. Is there a software that can replace the "NA" in the HDF file with other values?
Thanks!

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Re: SeaDAS-MOD04

by OB.DAAC - SeanBailey » Sat Dec 17, 2022 1:29 pm America/New_York

I'll reiterate that it is not a bug in SeaDAS. The HDF file is incorrectly written. Even the HDF4 user guide states the assumption that the fillValue should be of the same type as the data set:

"SDgetfillvalue reads the fill value which has been set for the data set specified by the parameter sds_id. It is assumed that the type of the fill value is the same as that of the data set."

There are tools that can edit HDF4 files. As I recall (although memory may be faulty) the HDFGroup's HDFView program can edit HDF files.

You may wish to communicate with the LAADS support team on this issue, as it is a data issue, not a SeaDAS issue.
For what it's worth the Collection 6 version of that file can be read by SeaDAS, since the QC field does not include a fillValue attribute.

That said, Bing did indicate that a future release of SeaDAS will account for this incorrectly written data.

Sean

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Re: SeaDAS-MOD04

by fjqkszcg » Sun Dec 18, 2022 1:36 am America/New_York

Hello!
Ok, I will contact LAADS support team, thank you!

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Re: SeaDAS-MOD04

by LAADS_UserServices_M » Mon Dec 19, 2022 11:41 am America/New_York

In order to properly respond to your question about MOD11 product please post a question and select LP DAAC tag from DAAC because MOD04 is related to LAADS and MOD11 is related to LP DAAC even if you downloaded it from ladsweb.
Regards,
LAADS User Services

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fjqkszcg
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MOD11-Proj

by fjqkszcg » Mon Dec 19, 2022 12:31 pm America/New_York

Hello!
Data MOD11 (Land Surface Temperature, V6.1), for example, MOD11_L2. A2022067.0315.061.2022068083624. HDF, SeaDAS software
can't read! Data MOD11 (Land Surface Temperature, V6), for example, MOD11_L2. A2022067.0315.006.2022068084828. HDF, data
itself without geographic longitude and latitude, in SeaDAS software can be read, but can't projection, Excuse me, how to
solve the problem?
Thanks!

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