What two methods can be divided according to the encryption area?

Independent model method and strip method.

Independent model method is triangulation of regional network with single model, double model or unit model composed of several models as the basic unit for overall adjustment operation. In the banded method, firstly, a single model composed of multiple stereo image pairs is connected into a banded model, then the single model is connected into a banded model to form a banded free network, and then the banded model is regarded as an absolutely oriented unit model of the banded network.

Analytic aerial triangulation refers to the method of encrypting control points indoors by using the inherent geometric characteristics of photos in aerial photogrammetry. That is, according to a small number of field control points, the corresponding route model or regional network model in the field is established through photogrammetry, so as to obtain the plane coordinates and elevation of the encrypted points.