Table 4 Standard deviation ellipse parameters of NSIBs in Chinese urban agglomerations.
Year | Center of gravity X coordinate(°E) | Center of gravity Y coordinate(°N) | X-axis length (km) | Y-axis length (km) | Ellipse direction angle(°) |
|---|---|---|---|---|---|
2015 | 116.305 | 29.831 | 674.979 | 1203.740 | 23.794 |
2018 | 115.143 | 31.608 | 1234.119 | 1044.554 | 48.799 |
2021 | 115.520 | 32.199 | 1117.492 | 1083.101 | 77.144 |
2023 | 115.454 | 32.168 | 1131.848 | 1066.327 | 123.494 |
