Alas, link nicht gut: http://immersivespaces.com/about/video1/

It looks like this breachmay be a common source of the leak. A sham that Whrrl didn’t feel free to name and shame the leaker.

It reminds me of how the established GIS players failed to see the real opportunity of web mapping and let Google Maps create the category instead. They could leapfrog – there’s still so much more that could be done using structured data that Google doesn’t seem interested in – but they’re sticking with the old enterprise model instead; hostage to their existing supply chains and customer base. Maybe it’s time for some spinoff companies to emerge.

You point out that A-GPS needs a data connection to download an ephemeris every so often. Indeed it does. That hardly makes me “100% wrong”. iPhone mapping uses data, which I’d already pointed out; but you can get by with occasional wifi. It does not *require* a *data service* from your telco. And if you read back, you’ll see that’s all I claimed.

Your suggested test of disconnecting the iPhone from all data networks for a week would indeed prove your point about ephemeris download, which I happily concede. However it is not “a more accurate experiment”, because it’s not how iPhones are actually used. This is a socio-technical system, so case studies (with all their limitations) are in fact our best method of gathering meaningful data. In practice, my wife’s iPhone which has no data service is still getting getting the benefit of A-GPS.

Early A-GPS systems *did* use the control plane, as you admit. And current systems do something very similar over the user plane; they’re still pinging towers. They use the data network, but as the very nice Ars Technica article you cite points out network operators support it even for devices that do not have *data service*.

This is piggybacking on existing data infrastructure, which is not absurd at all; it’s also what Skyhook does. The Ars article is roundly in praise of A-GPS, and contains some harsh criticisms of the cold start problems that plague unassisted GPS. I really don’t see how it helps your case here, except that it points out that control-plane systems are no longer in use. But once again, I had already said that I didn’t know what kind of A-GPS the iPhone was using, and I assert that it’s not the point. And again you misquote me: I did not say that A-GPS doesn’t “use data services”, I said that the iPhone’s A-GPS doesn’t “require a data service”.

So dammit, read back, I was careful in my assertions. You can demolish straw men all you like, but you’re disproving something that I did not claim.

In any case this has no bearing on my robust, reasonable and wise point that the iPhone and iPad’s A-GPS is not fake and will be excellent for location-based services, as opposed to your unsupported assertion that it “cannot compare” to a dedicated device like a TomTom.

You then complain that I’m talking about old devices. I specifically acknowledged that newer Garmin devices are undoubtedly better than my old iQue. Nonetheless that was a “serious” device made by a company you cited. I know internet time is fast, but the iQue 3600 launched in 2003, was still being sold and actively promoted by Garmin in 2007 and was discontinued only in June 2008. For you that counts as “relics from a time when dinosaurs walked the Earth”?

Now, I emphatically agree that the iPhone is the wrong GPS to take on a serious bushwalk. So is a TomTom. It’s not the point you expressed earlier but it’s a good one and I agree with it. I think that iPhone users are only too aware of its battery limitations, but if someone wasn’t and thought they could take it instead of a map and compass or a proper hiking GPS on a three-day hike to the Bluegum Forest, I’d strongly advise them not to be daft. A lack of replaceable internal battery isn’t the problem, as there are multiple external battery solutions available (including solar rechargers), but there’s no way I would consider the device robust enough to stake my life on. I would require something shockproof and waterproof instead, and I’d still take a map and compass.

I agree the iPhone compass is too often subject to interference, but it hasn’t been a problem for me while driving, and I’m prepared to accept that the altimeter is useless; I’ve never been curious about the altitude of my car. I believe you when you say you’ve had a different experience to me; are you using the TomTom app? If you are, then it might just be something about the configuration of your car. An external antenna is the usual solution, just as it is with any GPS device. Every review I’ve read of the TomTom for iPhone Car Kit indicates that it is every bit as good as a regular TomTom. Of course it is pricier to buy an iPhone plus the TomTom app and the Car Kit, unless of course you *already have the iPhone*. If you really want you can jailbreak and use a cheap bluetooth eternal GPS receiver, but that seems like a lot of bother to save fifty bucks.

Finally. What you call the “scientific journal article about how much the iPhone GPS sucks” is in fact a balanced review, and you are heinously mis-stating its position. The abstract does say that in their tests the iPhone’s A-GPS was less accurate than a dedicated GPS. That sounds like a big deal until you read the actual article and take a look at their methodology. “A-GPS locations were collected at outdoor sites under ideal conditions, i.e. excellent satellite visibility” (p. 14). What about urban canyons, the common scenario that I mentioned? Well, they confess that they didn’t test those in the section on limitations of their methodology. They did try indoors, where the iPhone switched to other positioning methods, which are less accurate than GPS, but they *didn’t even bother testing the dedicated GPS* because it would have given them nothing. By the way, their “low-cost GPS” is a Garmin GPSMAP 60Cx, $412 from my favourite GPS store. http://www.ja-gps.com.au/Garmin/handheld-gpsmap60cx/ – and a very nice piece of kit. All measurements were taken in Albuquerque, 59th in the US for metro population and around 1/10th the population of Sydney, so hardly the best-case for wifi density; nonetheless “WiFi and cellular positioning were able to obtain a position fix at most of the indoor sites where A-GPS failed”.

They go on to attribute the worst position errors to the iPhone snapping reported positions to the road network. Rather than attempting to get a position fix along a road where most driving and walking happens, the researchers had chosen random points on a map, in the middle of various fields (and excluding any points without perfect satellite visibility). They cite other studies of positions taken while driving along roads that give much better accuracy figures, and conclude that positional accuracy away from roads is likely to be less accurate.

So in the end this study weakens your claim that the iPhone is bad for driving directions, but it strengthens your new point – the iPhone isn’t the right GPS for bushwalking.

Personally, I’m interested in location-based services, and the standard canonical data point for a premises is its point of entry from the street. So for that purpose, locations that are accurate along roads will do nicely.

The iPhone is the worst smartphone except for all other smartphones so far. It’s made locative media an actual thing, instead of a dream. We can do much, much, better; but no-one has yet.