【大地测量学基础】200601 Introduction.ppt

School of Geodesy and Geomatics,WHU 1 Introduction 1.1 Definition and Classification of Geodesy Definition: the study of the shape, size, gravity field of the earth and the measurements on its surface 1.1 Definition and Classification of Geodesy(continue) According to the classical definition of F. R. Helmert (AD 1880), geodesy is the science of the measurement and mapping of the earths surface. This definition has to this day retained its validity; it includes the determination of the earths external gravity field, as well as the surface of the ocean floor. With this definition, geodesy may be included in the geosciences, and also in the engineering sciences (Gerke 1972) 1.1 Definition and Classification of Geodesy(continue) Classification: --By the type of measurements Geometric Geodesy Physical Geodesy Space Geodesy --By the size of surveying area Global geodesy Geodetic surveying Plane surveying global geodesy, geodetic surveying, and plane surveying Global geodesy is responsible for the determination of the figure of the earth including the complete external gravity field. A geodetic survey defines the surface of a country by the coordinates of a sufficiently large number of control points. In this fundamental work, the overall curvature of the earth must be considered. In plane surveying (topographic surveying, cadastral surveying, engineering surveying), the details of the land surface are obtained, the horizontal plane is in general sufficient as a reference surface. global geodesy, geodetic surveying, and plane surveying There is close interaction between global geodesy, geodetic surveying and plane surveying: The geodetic survey adopts the parameters determined by global geodesy, and its own results are available to those who measure the earth. The plane surveys, in turn, are generally tied to the control points of the geodetic surveys and serve particularly in the development of national map series and in the formation of real estate cada