Fig. 3. 3D surface derived from UAV

Fig. 3. 3D surface derived from UAV survey: (a) overview of the 3D model of thestudy site showing the camera exposure stations (the extent of (b) is shown in red);(b) detailed subset of the 3D surface model showing the detail in the topography.Note that this is not an orthophoto, but a 3D model with its facets coloured basedon the average colour from the photographs. (For interpretation of the references tocolour in this figure legend, the reader is referred to the web version of the article.)