Sorry for a simple question. But I really don’t get it statistics and histogram in SNAP. I’ve downloaded the landsat 8 product level 2, which should be atmospherically corrected and with surface reflectance values, but valus on x-axis are still in Digital Numbers probably? I’ve tried open it in ENVI at university and ENVI is also describing values in tables (compute statistics in ROIs) as DN.
Can anyone explain me a principle behind this? Thx
USGS stores DN in the GeoTiff files of Landsat 8. In the *_MTL.txt are conversion factors to radiances and reflectances stored.
If you use the MTL.txt file to open the L8 data you will get the radiances. There is a property which lets you switch to reflectances.
If not present, create a file ‘s3tbx.properties’ in the folder [USER_HOME]/.snap/etc
in this file ‘s3tbx.properties’ add the entry
s3tbx.landsat.readAs=reflectance
If you open the GeoTiff files individually you will get the DN values.