ISO 19155:2012 specifies an architecture that defines a reference model with an encoding method for an identifier of a place. The concept of "place" within ISO 19155:2012 includes "places" not only in the real world but also those in the virtual world. These "places" are identified using either coordinate identifiers, geographic identifiers, or virtual world identifiers such as URI. In ISO 19155:2012, an identifier of a place is referred to as a Place Identifier (PI). The reference model defines a mechanism to match multiple Place Identifiers to the same place. In addition, a data structure and set of service interfaces are also defined in this reference model. ISO 19155:2012 is applicable to location based services, emergency management services and other application domains that require a common architecture, across specific domains, for the representation of place descriptions using coordinate, geographic, or virtual world identifiers.