What do the marshes represent to Pip throughout Great Expectations?

I would say the marshes can also represent
emptiness. Pip is first at the marshes studying the names of his
family members who have passed away. He does so with a stick poking at their graves.
When the life of the convict comes in contact with Pip, Pip finds the desparation of the
covict almost immediately. When people are in that desparate state, they are empty,
waiting to be filled.

The convict's first need is hunger
and he looks to be filled by Pip. Out of fear Pip does help the convict, but I think
it's more than that. Pip has an empty life. This convict at least provided some action
for a time.

The life Pip leads in this small town feels
empty to him. This is why the book (among other reasons) is entitled Great
Expectations. Pip wants something more and this location at the marshes
represents the opposite of more, nothingness or emptiness.