Patent ID: 8089405

Claim:
A method for using geographic codes transmitted by a plurality of source devices, the method comprising: receiving, with a first client device, signals including geographic codes from at least one of the plurality of source devices, the geographic codes including an altitude of each of the source devices; extracting, with the first client device, the geographic codes from the received signals; decoding, with the first client device, the geographic codes to determine location information of each of the source devices; determining, with the first client device, a location of the first client device based on the location information; receiving, with the first client device, a location broadcast from a second client device; and performing, with the first client device, an action using the location information, the action comprising: retrieving a map of an area near the location of the first client device; modifying the map to include a first marker showing the location of the first client device and a second marker showing the location of the second client device; and outputting the modified map.