Chris Heathcote's presentation at ETCON: 35 ways to find your location: a tutorial about some of the techniques that can be used to find where we are in space. He claims that in 10 years' time, there will be no concept of lost. We have many way to know where we are. He compare those methods (accuracy, availability, reliability / trust, output useful to humans, output useful to computers, requirements for conversion (extra enablers needed) , acquire or refine?).

The methods:

the earth, the time, cultural clues (which cell phone operators available? which wi-fi providers? phonebox operators? phone number syntax? newspapers available? language being spoken?), ask someone, use a map, cell ID, angle of arrival, time difference of arrival (TDOA), observed time difference (OTD), GPS, WAAS/EGNOS and other GPS enhancements, post codes / zipcodes,street names (street corners / intersections, street numbers), business names, landmarks and littlemarks, phone boxes / public transport stops / utility markings, location street signs, geowarchalking, dead reckoning,wi-fi triangulation, broadcast TV/radio triangulation, IP lookup, encoding of location in access point name / location points, local servers / Rendezvous, bluetooth, RFID, who you are near (inference), objects you are near, the road most traveled

I like this very much, because it provides a nice review of cues human rely on. This nice piece of work is a first step for many locative media project :)