Maps are the 2D fields on which combat takes place. A map is destructable depending on what weapons the player uses.
Occasionally (very often in the Firing Range) an earthquake strikes naturally, which deals no damage but levels out the map to the point of largely removing digger holes, but not completely discounting damage to the terrain at the same time. Earthquakes will generally attempt to revert the map to a variation of its initial form, albet flatter.
The map mountain goats that can be purchased in the shop is the worst map.