A method for creating a map of at least one parking infrastructure. Unoccupied parking spaces inside the parking infrastructure are registered. Items of path information and items of environmental information are received by an external server unit. Items of path information are subdivided into path segments. The path segments are rectified by the external server unit. A loop recognition is carried out in order to create a geometrical map of the parking infrastructure. On the basis of the items of environmental information, occupied and unoccupied parking spaces along the path are acquired in order to ascertain unoccupied parking spaces inside the parking infrastructure. An external server unit and a system are also described.