摘要
针对某些大型调水工程东西跨距较大的特点,提出了特殊的减小长度变形方法,即将原参考椭球膨胀至高程投影面,再将椭球面大地坐标投影至圆球面,然后以工程线路的中轴线为伪中央子午线进行斜轴墨卡托圆柱投影。结果表明:斜轴墨卡托圆柱投影可建立统一的、满足投影变形要求的工程独立坐标系统,可同时减小高程归化引起的长度变形和高斯投影长度变形,避免了由于多个分带导致的误差和频繁的坐标转换;对于大型调水工程投影变形应要求不大于10 mm/km,则工程线路至线路的中轴线的距离应不大于28 km,即投影带的宽度应不大于56 km。通过与变形椭球高斯投影方法对比可知,斜轴墨卡托圆柱投影方法综合投影变形与前者相当,但在圆球面上进行计算和分析相对简单方便,容易推广使用。
Aimed at the features of some large-scale water diversion projects that the east to west crossing-distance is larger,a special method for reducing the length deformation is proposed. First,expanding the original reference ellipsoid to the height projection plane; second,projecting the ellipsoidal earth coordinate onto the spherical surface; finally,carrying out the oblique Mercator cylindrical projection by taking the pseudo central meridian as the central axis. The result shows that the oblique Mercator cylindrical projection not only establishes an integrated project coordinate system,but also reduces both the length deformation caused by the elevation domestication and the length deformation of Gauss projection at the same time,thus avoiding the error caused by several sub-zones and frequent coordinate conversion; with which the projection deformation must not surpass 10 mm/km and the distance from the project line to the central axis not surpassed 28 km for the large-scale water diversion project,i. e.the width of the projection must not surpassed 56 km. Through the comparison with the method of the alteration of Gauss projection based on oblique deformed ellipsoid,the comprehensive projection distortion from the method of oblique Mercator cylindrical projection with elevation domestication is equivalent to that of the former,but is simple and easy to make calculation and analysis on spherical surface,thus is prone to be popularized for application.
出处
《水利水电技术》
CSCD
北大核心
2017年第3期34-38,76,共6页
Water Resources and Hydropower Engineering
基金
湖北省水利重点科研项目(HBSLKY201608)
关键词
大型调水工程
斜轴墨卡托圆柱投影
投影变形
椭球膨胀
球面投影
large-scale water diversion project
Oblique Mercator Cylindrical Projection
projection deformation
ellipsoid expansion
spherical project
作者简介
何婵军（1983-），男，工程师，硕士，从事GPS数据处理与变形监测研究。E—mail：hecj-56031@163．com
