In Paulo Coelho's The Alchemist, I find that the setting of the desert, a generally barren place—without vegetation and little animal life—actually provides a great deal of information to Santiago, thereby making an enormous difference in his journey to achieve his Personal Legend.
When the boy (Santiago) wanders out into the desert (not too far from the oasis), he sees two hawks. In a state of near-sleep, he has a vision of the hawks fighting and believes that the vision warns that the oasis will be attacked. Though what Santiago "sees" is very simplistic, it conveys a message of great importance to the occupants of the oasis: this piece of land is considered to be "neutral territory" and for this reason, the people feel safe, assuming that no one will harm them.
Against Santiago's better judgment, he shares the vision with the leaders of the oasis. One elder alludes to the story of Joseph, the youngest of eleven brothers who was sold by his siblings into slavery, who became a great man in Egypt because he could decipher the meaning of dreams. The elder notes that there is supposed to be an agreement of peace in the oases, but also tells Santiago:
But the Tradition also says that we should believe the messages of the desert. Everything we know was taught to us by the desert.
In this instance, Santiago gives the elders information that can save them. While the desert seems as if it has little to offer the living, it is from this physical setting, ironically, that significant warning arrives, and the elders note that they never ignore the messages from the desert. This physical setting and what occurs there lends meaning to things within the desert that are about to change.