Principle of surveying are as follows:
i. To work from whole to part.
According to the first principle, the whole area is first enclosed by main stations and main survey lines as shown in figure above. The area is then divided into a number of parts by forming well conditioned triangles. A nearly equilateral triangle is considered to be the best well conditioned triangle. The main survey lines are measured very accurately with a standard chain. The sides of triangles are measured. The purpose of this process of working is to prevent accumulation of error.
ii. To locate a new station by at least two measurement from fixed reference points.
The new stations should always be fixed by at least two measurements from fixed reference points. Linear measurements refer to horizontal distance measured by chain or tape. Angular measurements refer to the magnetic bearing or horizontal angle taken by a prismatic compass or theodolite. The new station or ground point is located using linear measurement or angular measurement or both measurements.