I have some misunderstanding with Image Radiometric Correction and Atmosphiric Correction. I have seen YouTube video for this. I am working with Landsat 8 data and ENVI 5.1. I have seen a video "Atmospheric correction of Landsat 8 Using ENVI 5 0 3" I wants to know when I apply Flaash atmospheric correction? is it starts after the result of DOS? is it inbuilt with ENVI 5.1 'Radiometric Calibration Tool'? I request you Please share a movie/paper with whole correction process of Landsat 8 (which start with RAW tiff file of landsat 8 and end after essential radiometric and atmospheric correction of that image . I am a beginner of Remote sensing.