SfM techniques have been usedto generate accurate orthophoto mosaics from a multi-rotor UAV at 1 cm resolution with 10 cm absolute geometric accuracy (Turneret al., 2012), and the accuracy of the SfM derived point cloudswas quantified for a coastal erosion study, which concluded thatabsolute accuracies between 25 and 40 mm can be reached with a multi-rotor UAV flying at 40 m above ground level (AGL) (Harwinand Lucieer, 2012)