滇中引水工程独立坐标系统建立的关键技术研究

Key Technology on Establishment of an Independent Coordinate System for Water Diversion Project in Central Yunnan

云南滇中引水工程具有测区跨度长、平均海拔高、高差变化大等特点,独立坐标系统的建立难度大。本文根据投影变形理论,结合滇中引水工程的特点,提出了适用性的建立独立坐标系统的关键技术解决方案。用1°带的分带方式替代常规的国家3°带分带,有效地控制工程的高斯投影变形;推导了新的适用于高原长距离工程的抵偿投影面求取方法,并结合滇中引水工程实际给出了优化的抵偿投影面设置方案。使用本文建议的独立坐标系统,工程综合变形的最大值能得到最优控制。

A water diversion project in Central Yunnan exhibited several typical characteristics of the overall survey region, such as the extraordinarily long span, the high average altitude, and large ele- vation changes. Therefore, difficult to build independent coordinate system for this project. Based on the theory of projection distortion, we propose a key technology solutions composed of two parts. First, using the 1° projection zone to replace the regular 3° projection zone, Gauss projection distor- tion was effectively controlled. Second, a method for selecting a compensation projection plane was deducted to satisfy the needs of this water diversion project. An optimized solution for this project was found using the proposed independent coordinate system and efficiently controlled, the maximum com- prehensive deformation for this water diversion project in Central Yunnan.