Portals connect routes between floor levels.
Portals are connections between maps or parts of maps. Portals are most often used to indicate connections between floors, such as stairs, elevators, and escalators. Portals can also be used for other types of connections, such as skybridges or same floor transitions from one building to the next when the buildings are immediately connected but on a separate map.
When a visitor requests directions to a placemark on a different floor, the directions will take the visitor to a portal, switch maps, and then continue on to the destination.