In How to Read Literature Like a Professor, Thomas C. Foster takes the stance that the geography gives the story added meaning and depth. So let's consider Lord of the Flies as your example of how geograpy within a work of literature can add meaning:
1. The island-- The boys land on a completely uninhabited island somewhere in the South Pacific. As geography goes, and Foster points this out in his book, often moving the location of the setting farther south indicates a separation from rules and society. Especially with English authors (and William Golding, author of Lord of the Flies is English), the south represented a step away from the strict confines of British society. For the boys' island to be situated so far south, and really nobody knows exactly where they are, Golding makes the strong point that the setting of his novel is as far away from civilization and order as possible.
2. The beach-- The beach is wide out in the open, exposed to the light of the sun and the white gleaming sand of the beach. The wide open feeling represents a feeling of safety to the boys. Symbolically, the beach is as close to rescue and civilization as the boys can get, aside from leaping in the water and swimming home. They stay on the beach so they can spot ships and rescue; the beach becomes their link to civilization.
3. The jungle-- The jungle represents wildness and savagery. The trees are thick and tangled with 'creepers,' making the boys fearful of what might hide in its dark corners.
4. The mountain-- Often times in literature, great moments of truth and insight are discovered on the top of a mountain. In Lord of the Flies, Ralph insists on keeping a signal fire lit on the mountain on the island in hopes of being spotted by a rescue ship. Later, as the Beast (a dead parachutist) settles on the side of the mountain, the mountain comes to represent fear; it is after all, surrounded by the dark tangle of the jungle. One of the central characters, Simon, has a great moment of truth on the mountain, realizing that the beast was just a dead man, and then as he descends down to meet the boys, they mistake him for the beast and murder him. Think about that geographical symbolism that Golding just used. He goes from being on a mountain top, high with his discovery and insight, then he literally descends to meet the boys (but figuratively descends too, because the boys have all descended into savagery...) and they kill him.
Thomas Foster makes an invaluable point about the role of geography in literary works, and Lord of the Flies is certainly a poignant example of how a geographical reading of the text can reveal a deeper meaning.