Fig. 3 shows an overview and detailed section of the 3D model. The surface faces are coloured based on the average neighbourhood colour in the UAV aerial photographs. The model in Fig. 3 is deliberately not texture-mapped in order to show the true detail in the model. The 1 cm resolution orthomosaic is shown in (Fig. 1).
The results of the geometric accuracy assessment based on the 30 GCPs (Fig. 1) are reported in Table 1. The overal RMSE was 0.042 m, which is comparable to other SfM studies (D’Oleire-Oltmanns et al.,2012; Harwin and Lucieer, 2012; Niethammer et al., 2012) and better than our previous study (0.10–0.15 m reported in Turner et al.,2012). The 0.044 m error in the height value was subsequently used to define the standard deviation of the Gaussian error model in the Monte Carlo simulation. The magnitude of the errors in the orthomosaic and DSM is within the error margin and measurement precision of the GPS measurements that are used as the reference coordinates.