Research Article
Spatial Pattern of Underground Space Development in Major Cities in China: Evaluation and Analysis
Table 3
Corresponding standards for the closeness of UUS development level.
| Rank | Range of D | Level of development | Number of cities | Percentage of cities |
| Level 1 | >0.8 | Excellent | 0 | 0 | Level 2 | 0.6∼0.8 | Good | 6 | 15.39 | Level 3 | 0.3∼0.6 | General | 15 | 38.46 | Level 4 | 0∼0.3 | Poor | 18 | 46.15 |
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