The southwest mountainous area has high mountains deep valleys, and rapid rivers. The abundant water volume and huge drop have formed extremely rich water resources. National hydropower construction is blooming all over the southwest. The representatives Baihetan and Wudongde are on the Three Gorges level in terms of installed capacity and water storage scale.


The survey area for this trip is located on both sides of a certain river in Tibet. Hundreds of millions of years of water cutting have carved a deep ravine on the towering Qinghai-Tibet Plateau. From the highest snow-capped mountains nearby to the bottom of the valley where the river flows, there is a vertical drop of two More than a thousand meters, the horizontal distance is only six or seven kilometers. The difficulty of flying in such steep terrain is evident. The task of the survey area is to complete the terrain and feature survey in the early stage of construction of a hydropower station in Tibet. The survey area is a valley area with a length of 32km and a width ranging from 1km to 5km. The altitude is between 3300m and 4000m. The rapid changes in weather have increased the difficulty of aerial survey operations.

With the rapid development of urban construction in our country, urban underground space informatization is increasingly valued by industry managers - underground space data is an indispensable and important part of urban construction, realizing three-dimensional informatization of underground space and building a three-dimensional city , providing scientific and technological support for the rational development of urban underground space resources, has become one of the most effective measures to solve urban problems. Therefore, studying high-efficiency, high-precision, and all-factor three-dimensional information acquisition and expression methods in underground space plays a crucial role in promoting urban construction and improving the level of urban informatization.