The principle of aerial photogrammetry offers the possibility to build the digital model of the land (DTM) with high precision accuracy, offering approximately 100 points per 1 sqm.
Thus, by the data obtained by the UAV method, the digital 3d representation of the situation in the field is identical with the reality, compared to the classical method to obtain a DTM (GPS, Total Station) by which the land area is numerically represented z=f(x,y); obviously, it is an approximate representation, because the land has a discontinuous shape, and it is approximated by a continuous function.
The digital land model is a digital representation of the relief in space taking the elevation into account.

major advantages over the classic method

high precision

the possibility to provide multiple analyzes: flood studies, etc.