A method and apparatus for determining the geographic location of a user incorporates the sensing of a plurality of physical environmental parameters at the user's location. The parameter values are compared to corresponding parameter values associated with known locations, and a best-fit correlation is established. The identity of the determined location may be displayed to the user, or may be used to control a location-based operation, such as the unlocking of a safe, the transmission of an entry password, or the disabling of a piece of equipment. Persistence weighting values for different environmental parameters may be applied to improve the reliability of the correlation.