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robintw / Py6S

A Python interface to the 6S Radiative Transfer Model
GNU Lesser General Public License v3.0
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ASTER band 8 - PredefinedWavelengths #26

Closed samsammurphy closed 8 years ago

samsammurphy commented 8 years ago

ASTER band 8 in the PredefinedWavelengths class of wavelength.py does not seem to be correct. The Start Wavelength (2.25) is higher than the End Wavelength (2.244).

(line 732 of wavelength.py) ASTER_B8 = (-136, 2.250, 2.244)

The original 6S fortran code (attached) assigns the values of 2.21 and 2.39, respectively. ASTER.zip

However, the 6S values are also odd. This is because the fortran array for the band 8 spectral filter function has 76 elements, yet the spectral range (2.39-2.21) divided by the spectral increment (0.0025) would require a 72 element array.

robintw commented 8 years ago

Thanks for noticing that!

I agree that the 6S values are odd, but I think it's probably best for Py6S to just use the 6S values (with a comment in the code indicating that they're odd).

If you want to submit a Pull Request, I'm happy for you to do so (it'd be a nice easy first PR), but otherwise I'm happy to make the change myself.

samsammurphy commented 8 years ago

Thanks for you help with the PR

NB. the start and end wavelengths actually do correspond CORRECTLY with the 6S fortran code (i.e. I was mistaken previously because the Fortran code names the ASTER bands 3N and 3B .. as 3 and 4 .., this set me off by one)

robintw commented 8 years ago

Thanks for working that all out Sam - and well done for the first PR :)