mdCares
Guizhou, China,

md4-1000 in Emergency Surveying And Mapping in Guizhou Mountains


In August 2015 the Municipal Survey & Design Institute for Water Resources and Hydropower in Guizhou Province deployed their md4-1000 in an emergency surveying and mapping task for a key reservoir before flood season. The task was to investigate the number of residents and property status of the first-tier water conservation zone of the reservoir via GIS data collected from aerial photography with a md4-1000, and therefore assisting the government’s decision-making with GIS data support.

"The geographical conditions here are quite special – high altitude with a lot of mountains, and plenty of rain for over 200 days per year. Therefore, the low-hanging clouds make traditional manned helicopters unsuitable. Besides, the preparation work takes too much time. So in the past we’d use satellite remote sensing images. But since those images were not precise enough, we had to calibrate and complement the image data with field investigation. Furthermore, the instantaneity of satellite images is far from satisfactory, as they are only renewed once a year and may miss out certain areas blocked by clouds," the dean of the institute said. "We tried other UAVs for aerial photography as well, but it didn’t end well. A suitable UAV system for us should be VTOL, as there is little flat open ground for take-off and landing here with all the mountains; it should be reliable for BVLOS flights (beyond visual line-of-sight) as the mountains may easily block your sight; it should be waterproof for the changeable weather; it should be able to fly at a constant height above the terrain to improve the accuracy of aerial survey and mapping. Many so-called UAVs today are unreliable. You can’t even guarantee they can fly back, let alone complete aerial survey and mapping tasks."

This is the first field task for the institute since it acquired the md4-1000. Overcoming the interruption of continual cloudy and rainy weather, the drone completed its aerial photography task over a mountainous area of 43 km² in 3 days. "For an area of this size, it would have taken more than a month for the field investigation alone. But this time with the md4-1000, field investigation took only a week with the interruption of bad weather. Time and human costs were greatly reduced. With the stable attitude of the md4-1000 and the excellent flight route planning function, the aerial images taken were of great quality with a resolution of 4~8cm, which made post-processing the data very smooth. We are very pleased with the efficiency and results of this first field task."