I know that when using FLAASH in ENVI, you can produce a water vapor map (caveats considered) from your atmospheric correction.
My question is if it is possible to "back-calculate" a water vapor map if I used the QUAC atmospheric correction? Possible for other gases (e.g. methane or CO2)?
I'm not so much interested in the accuracy of the output as much as I'm interested in the methodology. I would like to understand better, if only in theory, how FLAASH calculates its water map and if its possible for me to try my own calculation of atmospheric contributions for each pixel from the QUAC correction, which considers only 'in scene' radiance values.