Author Affiliations
1School of Marine Sciences, Nanjing University of Information Science & Technology, Nanjing 210044, Jiangsu , China2National Satellite Meteorological Center, Beijing 100081, China3State Key Laboratory of Hazardous Weather, Chinese Academy of Meteorological Sciences, Beijing 100081, Chinashow less
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
True value | Predicted value |
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Positive | Negative |
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Positive | True positive(TP) | False negative(FN) | Negative | False positive(FP) | True negative(TN) |
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Table 1. Confusion matrix
Area | NDWI | MNDWI | CIWI | EWI | RNDWI | GNDWI | AWEInsh | AWEIsh | FNDWI | SWI |
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Standard deviation | 0.05 | 0.05 | 0.49 | 0.08 | 0.08 | 0.66 | 363.52 | 797.73 | 0.47 | 41.81 | Mountain | -0.11 | 0.11 | 0.24 | -0.44 | -0.03 | 1.23 | 458.06 | -2108.45 | -1.89 | 231.58 | Lake | -0.08 | 0.08 | 1.34 | -0.27 | -0.11 | -0.48 | 362.13 | -1911.47 | -0.49 | 255.20 | Paddy field | 0.01 | 0.16 | 0.68 | -0.21 | -0.24 | -0.10 | 1268.90 | -835.45 | -1.45 | 256.27 | Town | 0 | 0 | 0.06 | -0.293 | -0.039 | 0.925 | 782.24 | -152.43 | -0.92 | 352.14 | River | -0.09 | 0.05 | 0.03 | -0.38 | -0.05 | 0.92 | 1163.51 | -363.34 | -1.22 | 259.38 |
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Table 2. Threshold and standard deviation of water index model