水利水电枢纽工程往往建在深山狭谷之中,其规划设计阶段急需大比例尺地形图。这时若采用传统的测图方法,以常规的仪器进行施测,是难以达到《规范》中的精度要求。这是由于狭谷地形坡度较陡,务必在对 Water conservancy and hydropower hub projects are often built in deep valleys, the planning and design phase of the urgent need for large-scale topographic maps. At this time if the traditional mapping method, the conventional instrument for testing, it is difficult to achieve the “standard” in the accuracy requirements. This is due to steep slopes of valleys, be sure to right