Location-to-Service Translation (LoST) Protocol Extensions

An important class of location-based services answers the question, "What instances of this service are closest to me?" Examples include finding restaurants, gas stations, stores, automated teller machines, wireless access points (hot spots), or parking spaces. Currently, the Location-to-Service Translation (LoST) protocol only supports mapping locations to a single service based on service regions. This document describes an extension that allows queries of the type "N nearest", "within distance X", and "served by".