20000 km² national land survey finished in 8 months

“4 regions, total 22594 km² flighting task , 8 months, 3 UAVs”

The third national land survey in Guizhou province(China) is in the charge of GuizhouTDT Co, Ltd. GuizhouTDT has been using CW-10, CW-20, CW-30 these three UAVs accomplished orthophotography tasks that add up to 452 sorties and 22544 km², plus, oblique photography tasks add up to 29 sorties and 50 km²


Problems and Solutions in the surveying

As we mentioned that there are four regions in Guizhou province needed to survey, but each region has different situation with problems that have to make solutions for different problems. Technicians from GuizhouTDT summed up solutions for problems they have met in this surveying.

1. Large altitude difference in flight area

Yunnan survey area main distributed on each side of the Nu River valley which is the second longest canyon where exists large altitude difference. Thus, we decided to separate the survey area to get quality images, and adjust the operate according to the move of the sun. In this way, ensured flight 30 square kilometers in a sortie.

Additionally, for some steep mountains and short-space canyon areas, we recommend to take off on residential building if there has.


2. Rainy-days and Windy-days

From January to April, South Qianxi region had been raining and fogging all the time, sometimes had been sunning but with large wind. So pilots decided to operate, guerilla-style, means where the weather is good and where we go. When meet the windy-days, choose open landing to take off.

3. Scattered area

Zunyi is a region where the survey area is scattered and it’s extremely difficult to plan the route. To ensure the efficiency, we determined to add aerial points manually and survey multiple areas in one sortie.


4. Heavy-rain-days and forest cover area

Southeast Qian region and Tongren region had been raining heavily from June to August, meanwhile, these regions are covered by forests. In this situation, you have to check the weather before flight in case some emergency happened. And find take off place in advance. If it rains suddenly during the flight, we recommend to use trap cover the UAV instead of disassembly of the UAV until the rain is over.