So over the past couple of days there has been mass hysteria, questions in Congress, etc, over the fact that Apple is apparently recording all the locations you've been to with your iPhone without telling you, and storing it without encryption. The news was broken by my friend Pete Warden at Where 2.0 last week and has escalated rapidly since then. As someone who publishes their location anyway (you can see where I am right now by checking the right hand panel on my blog) I was less concerned about this than many, though I agree that Apple should make it clear that they are recording this information and give you the option to turn it off, plus it should be stored more securely.
However, yesterday Sean Gorman posted that he had analyzed his data, and the interesting thing is that it wasn't accurate - it showed the general areas he'd been to, but didn't reveal where he lived or where he worked. And then I also found this post by Will Clarke, followed by this one, which also conclude that whatever the data is, it isn't your accurate location (though I think Will prematurely concludes that it is cell tower locations - Sean's analysis suggests that isn't the case, though it seems it may well be related to this).
I just had a good chat on the phone with Pete about these posts, and about my findings which I'll get onto in a moment, which similarly conclude that whatever is being tracked, it isn't your accurate location. Pete said that their conclusions were similar, but also that he didn't think it was simply cell towers. I know that my iPhone knows my location much more accurately than the locations that I see in the data I've looked at. For me, as for Sean, there was no cluster of points either at my home or my office. Pete asked me if I'm on WiFi rather than 3G at home and at work, and the answer is yes, so there may be some clue there.
But the main point of these posts, and mine, is that this data does NOT indicate where you live, where you work or any exact locations you've been to. This is not reflected in most of the reporting you see about the topic.
I thought I'd share some screen shots of maps that I got, which I actually thought were cool :). Since I travel quite a bit, I have a few interesting examples which might give some clues as to what this location data actually does represent. The detailed (larger scale) maps here show a grid of dots, which is something introduced by Pete's map display tool rather than how the underlying data is. I will try to play around a bit more to get at the raw data, but thought I would share these initial findings first.
So to start with, here's an overview of my world travels of the past few months, which seems pretty accurate, and goes back to at least September:
Here's a view zoomed in on the US. The interesting thing here is that New York has the largest bubble over it, but I only spent two days there on a recent trip (1 day in Manhattan, 1 day on Long Island). Denver where I live has a much smaller blob.
Here's a map of Colorado - there seem to be quite a few outliers here on the south side of the map - I think that the closest I've been to these in recent months is Keystone, where you see a cluster of dots. Some of these dots are probably 50 miles away from where I was.
Zooming in on Denver, you see a lot of activity. I'm sure I haven't covered Denver quite as comprehensively as the dots here suggest.
In this map of downtown Denver you see the gridding which somewhat obscures the underlying data. However, the largest dot is some way away from my home (which as I think everyone knows is above the famous Wynkoop Brewing Company), and the dots are fairly evenly spread - these certainly do not indicate where I spend most of my time downtown.
Similarly, my office (where I usually work a couple of days a week, the other days I work at home) does not jump out on this map of the Denver Tech Center (as you can find out from our web site, the Ubisense office is at 5445 DTC Parkway).
On to my UK travels - I think the data includes two trips there. There seem to be quite a few outliers here also, and some fairly large clusters in places I just passed through on the train. I spent most of my time on these trips at my mother's house in Cropston, just north of Leicester, which isn't reflected in the data. I spent some time in London, but it has a disproportionate representation on the map (as New York did in the US map).
Zooming in to the Leicester area, you can see Cropston just to the north of the city, which is where I spent nearly all my time, and this has no readings. I didn't travel around Leicester nearly as much as the dots would suggest. So this map is very misleading in terms of where I spent my time in this area.
This map of Zurich is interesting: I connected through Zurich airport in November, en route to Denmark. I spent maybe 3 hours in the airport and didn't leave it, but you can see lots of outliers, which are up to about 20 miles away.
Here's a map of my trip to Denmark, where I spent time in Copenhagen, Aarhus and Naestved. The interesting thing on this one is that I just drove straight across the island of Funen (Fyn) in the middle of the map, but you can see quite a scatter of readings on either side of the road, especially to the south on the east side of the island.
Almost at the end ... I included this map of Paris as I thought it was interesting that we traveled from London to Paris and back on the Eurostar train, but no points show up along the route. There's an odd horizontal line of locations to the north of Paris, but nothing apart from that between Paris and London.
And finally an example from Sydney. This shows a disproportionate number of readings at the airport in the south, where I just arrived and left but didn't spend any time. It doesn't show that I spent a good amount of time downtown, and I gave a talk in Paramatta where there is just one isolated dot. I stayed with friends north of Sydney but again you can't tell where.
While I don't want to be an apologist for Apple, and what they are doing here is careless at best, my general conclusion is that this is likely something unintentional, similar to the Google Street View WiFi data fiasco. If Apple wanted to track your location history, why wouldn't they use your accurate location, which I know my phone knows much more accurately than is shown in the data in these files.
The interesting question for us geo-geeks is exactly what the location data is - something related to cell towers seems plausible. I will try to poke around in the raw data a little more. Since I have a few interesting example cases, am happy to share my data if anyone wants to look at it. Pete just tweeted that there is another table with WiFi locations, that would be an interesting thing to explore.
Update: I've done a new post which includes maps with the raw data, using Google Fusion tables. Doesn't change the conclusion that the data doesn't accurately represent your actual location, but does show some interesting new patterns.