Surveying, a means of making relatively large-scale, accurate measurements of the Earth’s surfaces. It includes the determination of the measurement data, the reduction and interpretation of the data to usable form, and, conversely, the establishment of relative position and size according to given measurement requirements.
Thus, surveying has two similar but opposite functions:
A. The determination of existing relative horizontal and vertical position, such as that used for the process of mapping.
B. The establishment of marks to control construction or to indicate land boundaries