基于椭球面大区域小比例尺地球表面对象表达方法研究-地图学与地理信息系统专业论文.docx

Subject ：Expression Method of small-scale surface of the Earth object based on a large area of the ellipsoid Specialty ：Cartography and Geographic Information System Name ：Wang Wei (Signature) Instructor ：Guo Lan (Signature) ABSTRACT Traditional map projection establishes corresponding functions according to certain laws of mathematics, this solved conversion problems from the ellipsoid to plane. But deformation will produced during the conversion, such as length (distant), angle (shape), and area deformation. This has brought difficulties in data seamless splicing and limitations in geodetic measurements and drawing. Reference ellipsoid is the closest to the earth surface which can be expressed by mathematical methods, and it is also the datum plane of geodetic calculation. So expressing surface objects on ellipsoid will be the most appropriate map manifestations which can avoid deformation, solve the expression problems in digital map and GIS effectively in large or worldwide area. This paper is on the basis of present preliminary studies on ellipsoid electronic maps. The earth line interpolation method is be re-chose by comparison, that is to say this research applies Bessel earth formula to solve the earth, concentrates the earth line by program, and last shows the result. The main research content and results are summarized as follows: On the basis of analyzing traditional map projection theory, this paper discusses traditional expression methods of surface objects with small-scale in large area.And the various methods discussed were compared, summed up their inadequacies and further emphasized the importance of the expression of surface objects based on the ellipsoid. In view of the concepts and applications of digital maps which are popular online, the concept of ellipsoid electronic maps has been further elaborated, as well as the discussion on its future application direction. This paper compares the earth line interpolation methods on the base of the