The boat is in front of what?
The boat is in front of the city.
    src        edge_attr  dst
0     1               by   12
1     1      in front of   11
2     1               by    4
3     3      in front of    7
4     3           behind   12
5     3  to the right of    6
6     4               by    1
7     6   to the left of    3
8     6               by   12
9     7           behind   11
10   10               on   11
11   10               on    4
12   11               in   12
13   11             with   10
14   11      in front of    7
15   11               on   12