 This study examined the effectiveness of different numbers of ground control points, GCPs, in improving the accuracy of unmanned aerial vehicle, UAV, derived digital surface models, DSMs. It was found that the use of four or more GCPs resulted in the most accurate DSMs, with vertical errors ranging between 0.08 and 0.14 meters. Additionally, the study showed that the closer the GCPs were to each other, the lower the vertical error. This article was authored by Toby N. Tonkin and Nicholas G. Midgley.