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Applied-GeoSolutions / gips

Geospatial Image Processing System
GNU General Public License v3.0
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Landsat7 ESUN #493

Closed bhbraswell closed 6 years ago

bhbraswell commented 6 years ago

I can't remember if there is some reason why GIPS uses different ESUN values (a) than USGS recommends (b)

(a) 'E': [2638.35, 2031.08, 1821.09, 2075.48, 1272.96, 246.94, 90.61, 369.36, 0, 0] (b) https://landsat.usgs.gov/esun

ircwaves commented 6 years ago

For Landsat 8, USGS doesn't provide the ESUN values. The differences arise from differences in the Thulier solar spectrum (as recomended by the Committee on Earth Observation Satellites (CEOS)), versus the ChKur solar spectrum used by the folks at Spectral Sciences (MODTRAN).

bhbraswell commented 6 years ago

THANKS

bhbraswell commented 6 years ago

Does your statement apply also to L7? That was actually what I was wondering about. I'm just noting that the table on the USGS site for L7 has different numbers. Sorry if I'm missing something.

ircwaves commented 6 years ago

Yes, it does apply to LE7. It would introduce noise into processing to use different solar radiance spectrums for different sensors, so they all use the CEOS-Thulier coefficients.