Quantifying Tufa Growth Rates (TGRs) using Structure-from-Motion (SfM) Photogrammetry

The production of high-quality digital surface models (DSMs) is an increasing interest throughout the various geomorphometry studies. Consequently, a wide range of advanced geospatial methods has been used at different scales. Despite the fact that Structure-from-Motion (SfM) photogrammetry is one of the most popular methods until now it has not been systematically applied in the studies of tufa formation dynamics (TFD). In this paper, we propose a framework for using SfM photogrammetry and GIS tools in the measurement of tufa growth rates (TGRs). TGRs were measured on two limestone plates (PLs) within the area of Roski waterfall in Croatia. Four submillimetre resolution DSMs of tufa have been created. TGR was 0.407 mm for a six-month period. Checkpoints were used to calculate errors. The results confirm the efficiency of the SfM at this scale. Research shows that photogrammetric measurement system design can produce extremely dense point clouds with high horizontal and vertical accuracy. The application of SfM and GIS in the measurement of TFD can be the great methodological improvement for specific geomorphometric applications at smaller scales.