What are the basic techniques of geodesy?

I. Geodesy, also known as geodesy. According to the classic definition of the famous German geodesist F.R. Helmert, geodesy is the science of measuring and characterizing the surface of the earth. That is, the study and determination of the shape and size of the Earth and the Earth's gravity field, as well as the determination of the geometric position of points on the surface. It also includes the determination of the Earth's gravity field and the topography of the sea floor and is a branch of surveying and mapping.

II. BASIC TECHNIQUES:

There are traditionally two approaches to solving geodetic tasks, geometric and physical.

1, the geodetic equation of the so-called geometric method is to use geometric observations through triangulation and other methods to establish a horizontal control network, providing the horizontal position of the ground point; through leveling methods, to obtain geometric elevation difference, the establishment of elevation control network to provide the elevation of the point.

2, the physical method is to use the earth's gravity and other physical observations through the theory and method of the earth's gravity field to push the geodesic level relative to the distance of the earth's ellipsoid, the flatness of the earth's ellipsoid and so on.