In wilderness encounters, the top two rows and leftmost two columns are duplicates. The bottom two rows and rightmost two columns are always all grass.
It looks something like this:
Code:
~~.~..~.~.~~~~.~..
~~.~..~.~.~~~~.~..
~~~~.~~~~~.~~~.~..
..~~.~~..~~~.~~~..
~~.~.~..~~~.~~~~..
..~.~~.~~~~.~~~~..
~~~.~~..~....~~~..
..................
..................