How does Dickens use setting to convey the mood at the opening of Great Expectations?

Dickens establishes a dark and foreboding mood for the story from the beginning by the description of the marshes and his hints at trouble to come.  
Dickens uses the marshland setting to establish an ominous mood. The story begins with young Pip describing the marshlands. 

Ours was the marsh country, down by the river, within, as the river wound, twenty miles of the sea. My first most vivid and broad impression of the identity of things, seems to me to have been gained on a memorable raw afternoon towards evening (Chapter 1). 

The mood comes from the use of a marshland, a place of spooky Gothic imagery and young Pip’s coming adventure.  Pip describes the marshland as a “bleak place overgrown with nettles” and the first event of the book takes place in a cemetery, where Pip visits his family members. His mother, father, and siblings are all a row of headstones. We learn later Pip has only one surviving relative, a sister who beats him. 
When the convict arrives, his condition also demonstrates the harsh landscape. 

A man who had been soaked in water, and smothered in mud, and lamed by stones, and cut by flints, and stung by nettles, and torn by briars; who limped, and shivered, and glared and growled; and whose teeth chattered in his head as he seized me by the chin (Chapter 1). 

In addition to creating a mood of fear and confusion, the convict’s condition adds to the feelings of danger of the landscape. It makes Pip seem even more alone. Here is a small boy, in a cemetery, in an unforgiving marshland, with almost no family. 
This event will be important in Pip’s life because the convict he meets later becomes his secret benefactor. Pip's expectations play both a positive and negative role in his future. These events are foreshadowed by the dark nature of the marsh scenes in the early chapters.