Questions about the level3 remote sensing reflectance data of MODIS images

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zhuyaopu
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Questions about the level3 remote sensing reflectance data of MODIS images

by zhuyaopu » Tue Jun 04, 2024 4:38 am America/New_York

When I open the Rrs data using ENVI software, why is each pixel value of the image more than 10000 negative? In theory, shouldn't the remote sensing reflectance value be between 0-1?Thank you very much for answer my question!!!

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OB.DAAC - SeanBailey
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Re: Questions about the level3 remote sensing reflectance data of MODIS images

by OB.DAAC - SeanBailey » Wed Jun 05, 2024 7:15 am America/New_York

The Rrs data are stored in the L3 mapped netCDF files as scaled short integers. If your software does not apply the scale_factor and add_offset information (contained in the variable attribtues) to convert the scaled integers into floating point values, you will need to do so after reading the data from the file. The equation is simple":

geophysical_value = scaled_value * scale_factor + add_offset

Regards,
Sean

zhuyaopu
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Joined: Tue Jun 04, 2024 4:25 am America/New_York
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Re: Questions about the level3 remote sensing reflectance data of MODIS images

by zhuyaopu » Wed Jun 05, 2024 7:47 am America/New_York

Dear Mr.SeanBailey:
I see,thank you for answer my question,your answer is very helpful to me.Sending you my best wishes for a great day!


zhuyaopu

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