This disclosure is directed to positioning and mapping based on virtual landmarks. A space may include a plurality of signal sources (e.g., wireless access points (APs), cellular base stations, etc.). The space may be virtually divided into a plurality of regions, wherein each region in the space may be associated with a virtual landmark. Virtual landmarks may be identified by a signature comprised of measurements of wireless signals received from the plurality of access points when at the associated region. A device position may be approximated based on signal power magnitude and variance measurements for wireless signals received at the virtual landmark. Devices may employ an algorithm such as, for example, Simultaneous Localization and Mapping (SLAM) for positioning and map creation in the space without the need for GPS signals, specialized signaling equipment, pre-navigation device training, etc. Navigation/mapping may also account for space changes, signal source position changes, etc.