Yang, H.; Li, H.; Gong, Z.; Dai, W., and Lu, S., 2020. Relations between the number of GCPs and accuracy of UAV photogrammetry in the foreshore of the sandy beach. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 1372–1376. Coconut Creek (Florida), ISSN 0749-0208.

The combination of UAV (Unmanned Aerial Vehicles) and SFM (Structure from Motion) algorithm is an advanced method. This method makes the observations of sandy beaches more efficient and accurate. The DEM (Digital Elevation Model) from this method can encode elevation data and create highly detailed digital terrain models with a root mean square error (RMSE) of only 10 cm. But needing too many GCPs (Ground Control Points) to guarantee the accuracy of DEM is a main drawback of this method. This paper is aimed to solve this problem and assess how the number of GCPs will impact the accuracy of UAV photogrammetry to find the optimum number of GCPs.