| Valeur | Catégorie | le cas | |
|---|---|---|---|
| 1 | By sewers | 24 |
0.2%
|
| 2 | Protected canal | 65 |
0.5%
|
| 3 | Opened canal | 86 |
0.6%
|
| 4 | Swallow-hole | 22 |
0.2%
|
| 5 | River | 5 |
0%
|
| 6 | Hole | 1044 |
7.2%
|
| 7 | Nature | 8687 |
60.2%
|
| 8 | In the yard | 1813 |
12.6%
|
| 9 | In the street | 2672 |
18.5%
|
| 96 | Other | 4 |
0%
|
| 99 | 2 |
0%
|