What is empty three encryption?

Aerial triangulation is a survey method that encrypts control points indoors according to a small number of field control points in stereo photogrammetry, and obtains the elevation and plane position of the encrypted points.

Features: high encryption and good confidentiality.

Aerial triangulation is generally divided into two types: analog aerial triangulation, that is, optical mechanical aerial triangulation; Analysis of aerial triangulation, commonly known as computer encryption.

A method of encrypting indoor control points by using the inherent geometric characteristics of photos in extended data aerial photogrammetry. That is, shooting continuous aerial photographs with certain overlap and using a few field control points.

Through photogrammetry, the route model or regional network model corresponding to the field is established, so as to obtain the plane coordinates and elevation of the encryption point. Mainly used for topographic mapping.

Reference Aerial Triangulation _ Baidu Encyclopedia