What are the advantages and disadvantages of UAV low-altitude photogrammetry?

Advantages: the flying height and imaging clarity can be set as required; Because flying under clouds, it is less disturbed by clouds; The runway requirements are not high, and it is convenient to choose the landing runway; The aerial photography cycle is short and the results are quick.

Disadvantages: poor endurance, less one-time coverage, not suitable for large-scale aerial photography; The load of UAV is limited, and many cameras carried by UAV are not professional mapping cameras, so the accuracy of aerial photography needs to be verified. If the altitude is not enough, the flying quality will be affected when the wind is strong.