as pointed out by eric kansa, a reliable geolocation service for the iPhone would be a really neat thing. the problem is how to implement such a service. since the iPhone pretty seamlessly hops between edge and wifi networks, it also pretty often changes its ip address, which makes reliable geolocation a bit tricky. looking at the places where i use my iPhone, a geolocation service such as ipligence makes me travel very fast, even though in reality i am just walking 10min:
- at home, i am identified as being in santa rosa, california (this is where my internet provider is located).
- on my way, the ip assigned to me by at&t's edge resolves to london, england (god knows why at&t addresses are resolved to that).
- at the office, the location is correctly resolved to berkeley, california.
and since the iPhone can easily hop onto any (well, most...) wifi networks, and the way how these networks assign addresses (or even map them by using network address translation) is unknown, the good old ip way of geolocating an iPhone is probably doomed.
what else could be done? well, at&t knows where i am most of the time, because they can locate me by the mobile phone cell i am currently using. how to get that to a service? a pretty web-compliant way would be to use an http request header, which contains my geolocation in each http request. there is some related work for location for the session initiation protocol (sip) and the question of how to handle emergency calls, but there currently does not seem to be any attempt to standardize geolocation information in http (there was a draft four years ago, but it apparently died). but maybe i am missing something?
of course, such a functionality would be a huge privacy issue, iPhone users then would practically broadcast their location permanently to every web site they are visiting, so such feature should probably by disabled by default and be clearly signaled when being enabled. but since at&t, such as all mobile carriers, stores the complete location dataset of any user anyway (and very likely makes them available to authorities whenever they ask for it), the privacy issue is not something that has not been there before. it is more the question of how easy it should be for regular web sites to provide location-based services.
in a first version, the geolocation could be inferred from the mobile phone cell, this could be done as a simple software update. in a more accurate second version, a revised version of the iPhone could contain a Global Positioning System (GPS) device, enabling much more precise locations than just mobile cells.
and btw, location information could also be interesting for iPhone apps locally, such as the navigation feature in the mapping app, which currently is completely oblivious to its location and needs to be navigated along a route by pressing forward
and back
buttons.
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