Fig. 1. Technology roadmap

Fig. 2. Schematic diagram of determining optimal segmentation threshold based on Otsu (shown by dotted abscissa)

Fig. 3. Comparison of extraction effects of 10 band index in different experimental areas

Fig. 4. F1-score of water identification results of all water index in different areas. (a) Mountain; (b) lake; (c) paddy field; (d) town; (e) river

Fig. 5. False alarm rate and dismissal alarm rate of water identification results of all water index in different areas. (a) Mountain; (b) lake; (c) paddy field; (d) town; (e) river

Fig. 6. Average accuracy indexes of each model in different regions. (a) F1-Score; (b) false alarm rate and dismissal alarm rate

Fig. 7. Display of recognition effect of each index for land and water boundary. (a) Paddy field area, rectangular box as main research area; (b) false color composite map of research area; (c)-(l) water body recognition results corresponding to each index model

Fig. 8. Identification accuracy of each index in mixed area of land and water. (a) F1-score; (b) false alarm rate; (c) dismissal alarm rate

Fig. 9. Variation of reflectance of different land features with Sentinel-2A MSI band