"Grid maps are a useful tool in combat, as they can be used to keep track of where everyone is. Such a map is included in the adventure Riddermound at the end of this Quickstart. Each square on the map represents an area of 2×2 meters. The map also contains doors, walls, and other details." - Quickstart, page 14.
Map: An adventure site is best illustrated using a map with a 2-meter grid. - Beta, page 107.
Nevertheless, every map should have its scale on it.