What is the main task of measurement? What basic principles should be followed in measurement?

The basic task and function of survey control surveying is to study the precise determination and description of the spatial position of ground control points and their changes. Based on the basic theory of geodesy, it is developed and formed with engineering construction survey as the main service object, providing useful spatial information for human social activities. Therefore, in essence, it is a geotechnical engineering information discipline, an important branch of geoscience and surveying, and a basic and applied discipline of engineering construction surveying.

It plays an important role in cultivating surveying engineering professionals. The service objects of control survey are mainly various engineering construction, urban construction and land planning management. This determines that its measurement range is smaller than that of geodesy, and it also has diversified characteristics in observation means and data processing methods. As the service object of control survey, engineering construction can be divided into three stages: design, construction and operation.