1. A system for selecting beacons from which to infer a location of a mobile computing device, said system comprising: a memory area for storing a set of beacon identifiers, said beacon identifiers corresponding to beacons observed by a mobile computing device, said beacons being located within a first geographic area as observed by the mobile computing device, said memory area further storing beacon reference data and a confidence circle associated with each of the beacon identifiers, the confidence circle representing a degree of confidence in the beacon reference data corresponding to the beacon; and a processor programmed to: receive the set of beacon identifiers from the mobile computing device; identify, based on the beacon reference data stored in the memory area, one or more of the beacon identifiers corresponding to outlying beacons located on an edge of the first geographic area, the outlying beacons being identified based on the beacon reference data associated with the beacons; remove the identified beacon identifiers from the set of beacon identifiers stored in the memory area; select, from the set of beacon identifiers and based on the confidence circles associated therewith stored in the memory area, a subset of beacon identifiers corresponding to beacons whose confidence circles each overlap with each other; and determine a second geographic area based on the selected beacon identifiers and the beacon reference data and the confidence circles associated therewith, said mobile computing device being within the second geographic area, wherein the second geographic area is smaller than the first geographic area.