I am having a hard time figuring out how exaclty to do DOS. In the past I just used to locate a dark body of water and minus those values from bands 1,2,3,4,5 & 7. But more recently I heard it is better to look at a histogram and find the point where the DN values rise dramatically and us that as the constant value to subtract from each band. Chavez's method seems too complicated for me.
Also do I need to worry about just bands 1,2 & 3 or all bands.
Please advise ASAP.