In one embodiment, characteristics of signals of a plurality of Wi-Fi access points within a target area are determined at least in part from observing the signals during a traversal of a programmatic route through the target area by a scanning device. A location is calculated for each of the plurality of Wi-Fi access points based on the characteristics of the signals of the Wi-Fi access point, and stored in records of a reference database. A request from an application or service executing on a mobile device is received for a current location of the mobile device. Positioning software obtains characteristics of signals of one or more Wi-Fi access points observed by the mobile device from the current location. The positioning software computes the current location of the mobile device using at least the characteristics of signals observed by the mobile device and the location of Wi-Fi access points stored in the reference database, and provides the computed current location to the application or service.