It allows us to supress the shadow effects due to the relief.
There are two kind of shadows :
The shadows are directly corrected with the following formula :
With i the incidence angle and z the zenithal angle.
For the cast shadows, we are able to find, with the D.E.M., if a surface is lightened or not. This is done by comparing the angle from the surface to a close summit in the sun direction, to the solar incidence.
The atmospheric correction .