3. Indoor Navigation

While indoor navigation systems are available, they are not as popular as outdoor navigation systems. The major reasons for this lack of popularity are (a) navigation assistance in indoors (buildings) is not crucial as people do not consider getting lost inside of buildings and (b) options for making navigation decision in buildings are very few. For these reasons, indoor navigation systems are mostly designed for special needs populations (e.g., for visually-impaired) and special occasions (e.g., emergency). The main technologies for indoor navigation systems are geo-positioning to determine a user’s current location in real time (e.g., using RFID), wireless communication primarily for positioning, and databases for storage of spatial and non-spatial data (e.g., hallway network). CAD databases are one source of data for indoor navigation systems. Typical functions performed by indoor navigation systems are data retrieval (e.g., finding POIs), map creation (rendering of floor layouts), mapping (e.g., zoom in/out), geocoding (finding coordinates of POIs, origin, or destination addresses), routing (finding optimal routes from current location to a given destination location or between pairs of origin and destination locations), navigation (tracking the movement of the user in the building), and directions (a set of instructions to assist the user with a route through a building). Usability of indoor navigation systems includes mode of travel (walking, riding in a wheelchair), map presentation (hallway segments and networks), purpose of trip (commute, emergency), and user’s preferences with respect to POIs, routes, and map presentation.