Is it a harbor?
No, it is a beach.
    src        edge_attr  dst
0     1               on    0
1     1   to the left of   20
2     2  to the right of    7
3     4  to the right of   21
4     4  to the right of    7
5     5  to the right of    7
6     6   to the left of   20
7     6  to the right of    8
8     7   to the left of   19
9     7   to the left of   20
10    7   to the left of   21
11    7   to the left of    2
12    7   to the left of    5
13    7   to the left of    4
14    7   to the left of   17
15    8   to the left of    6
16    8   to the left of    9
17    8   to the left of   11
18    8   to the left of   20
19    9  to the right of   11
20    9   to the left of   20
21    9  to the right of    8
22   10               in   12
23   11   to the left of   20
24   11   to the left of    9
25   11  to the right of    8
26   13   to the left of   19
27   13   to the left of   20
28   13   to the left of   16
29   14   to the left of   19
30   14   to the left of   20
31   15   to the left of   20
32   16   to the left of   19
33   16  to the right of   13
34   17  to the right of    7
35   19  to the right of   13
36   19  to the right of    7
37   19  to the right of   14
38   19  to the right of   16
39   20  to the right of    6
40   20  to the right of    7
41   20  to the right of    8
42   20  to the right of    9
43   20  to the right of   15
44   20  to the right of    1
45   20  to the right of   14
46   20  to the right of   11
47   20  to the right of   13
48   21  to the right of    7
49   21   to the left of    4