This Is Not a Map
But surely at bottom was the motive that underlies all such fictional maps: the drive for realism, verisimilitude, mimesis--the nearly perfect representation of reality that makes a fiction seem to be true.
We trust a map. It describes the known physical world, the most certain knowledge we have, and in such detail that we can easily check its accuracy. If a map sometimes reveals things we didn't know.... And if you are making up a story that you want people to believe, even if just for a moment, you take all the reality you can get.
These are maps to persuade readers of what mere, unreliable text has already described: This story is true. It happened here.
On any map, some things must be included, and most things must be left out. The principle of selection will vary, depending upon the purposes of the mapmaker--roads and towns will be shown for a gas station foldout, but not necessarily elevation or topography. Like novels, maps have points of view (literally "orientation"). Their details are selected for a particular effect or use, like the details a novelist chooses in describing, say, Crusoe's island.
Robert Louis Stevenson understood instinctively that a map is a setting. A map is a fiction.
landscape and allegory have a strong affinity
Here, we may think, we have reached the ultimate point--two meanings of "plot" have simply folded into each other: The plot of ground or space where the story happens has become, without any intervening narrative words, the plot or action that is the very story itself. The map stands alone.