=== I have no ground truth reflectance data - how can I convert my radiance to reflectance? === '''A:'''[[BR]] The absence of ground reflectance data from your site means that an empirical method of atmospheric correction (e.g., [wiki:Processing/atmosphericcorrection#ENVI empirical line correction]) will not be possible. The best remaining option is to use one of the radiative transfer based atmospheric correction methods, two such models are: FLAASH (a tool in ENVI), and ATCOR4. If you are interested in having us process data for you in ATCOR4 or provide instructions so you can process data yourself, please get in touch.