椭球变换法在线状工程坐标系建立中的选定研究

Research on Selection of Ellipsoid Transformation Methods in Establishment of the Coordinate System for Linear Projects

针对高原长距离大型线状工程由于测区跨度广、平均海拔高、高差起伏大等特点导致测区投影变形过大的问题,推导了椭球膨胀法、椭球平移法和椭球变形法的数学模型,系统阐述了不同椭球变换方法建立工程独立坐标系的工作流程。以某高原长距离引水工程作为研究对象,将其以1°带进行分带,从椭球参数变化量、大地坐标变化量、高斯投影坐标变化量、长度投影变形4个方面对3种椭球变换方法的特点加以分析。结果表明,椭球膨胀法具有数学模型简单、计算方便,椭球参数变化量单一的特点;椭球变形法适合应用在被分割成多个投影带的工程衔接;椭球平移法对衔接大区域高斯投影坐标成果具有很好的效果。

As regards the long-distance linear project in plateau,a large projection distortion in the measured area may be resulted from the geographical features,such as wide span,high average altitude and great fluctuation of height difference.For this problem,several mathematical models are deduced,including ellipsoid expansion method,ellipsoid translation method and ellipsoid deformation method,systematically describing the working flow of establishing independent coordinate system for projects by different ellipsoid transformation methods.Take a long-distance water diversion project in plateau as the object of research.It is zoned by 1°,and the characteristics of three ellipsoid transformation methods are analyzed from four aspects:ellipsoid parameter variation,geodetic coordinate variation,Gaussian projection coordinate variation and length projection distortion.The results demonstrate that the ellipsoid expansion method is characterized by simple mathematical model,convenient calculation and singleness of ellipsoid parameter variation;the ellipsoid deformation method is suitable for interfacing project that is divided into several projection zones;and the ellipsoid translation method performs well in interfacing large-zone Gaussian projection coordinates.