More on Apple recording your iPhone location history

In my previous post I discussed how the location data being recorded from my iPhone actually wasn't very accurate, and certainly not accurate enough to tell where I live or work (based on the data I've examined so far, which is in a table called CellLocation in the iPhone backup, and is the data discussed by Pete Warden and displayed by his iPhoneTracker app, which is what I used for the visualizations in my previous post). Pete's app aggregated data to a regular grid, partly to provide additional security.

However, I was sufficiently intrigued to follow Pete's instructions to get at the raw data. My investigations with this reinforced the conclusion of the previous post, that the data does not accurately represent your location. But it did show up some interesting new patterns. I loaded the data into Google Fusion Tables and have made it public, you can view it here (and feel free to play around with it).

Here is an interesting map of downtown Denver, where I live.

This shows all the raw point data, with no aggregation or changes. There are actually no dots at all in the block where I live. However, there is a noticeable cluster in Coors Field, the Colorado Rockies baseball stadium which is 3 blocks away from where I live. I haven't been to the Rockies stadium over the time period that this data was recorded. There's also a strong cluster in Mile High Stadium, home of the Denver Broncos.

I would assume that there is additional cell phone infrastructure in these stadiums, to help cope with the heavy concentration of people. A quick Google search found this article about AT&T infrastructure at Coors Field

This reinforces the notion that at least some of these locations are the locations of cell equipment that your phone is communicating with. But I'm not sure that's the whole story.

Here's a map of Cropston, where I spent most of my time on my last two visits to England. It's a small village in a fairly rural area.

Here there are no locations shown in the village itself where I spent most of my time. A lot of the locations are clustered in towns or along streets, but some seem to be more in the middle of nowhere. Hard to draw any definite conclusions.

I just received a suggestion from Jonathan Barnes, via Pete Warden, that the HorizontalAccuracy field may be significant, with lower values indicated accurate locations via GPS. However, I did a quick test, for example this map filters to only show records with this field set to 500.0, the minimum value I found from a quick skim (Fusion tables seems to treat this as a string rather than a number), and while this reduces the number of records it doesn't offer any noticeable change in accuracy - it still includes all the readings from Coors Field and Mile High Stadium where I haven't actually been.

Pete also pointed me at another table in the backup called WifiLocation, which in my case was about 5 times larger than CellLocation. I have loaded this to Fusion Tables here. One interesting thing about this table is that data only shows up in North America (with one random exception in Munich, where I haven't been recently). It seems a little more focused on areas I've been to, but no more revealing in terms of showing specific locations where I've spent time.

As I said, feel free to play with the tables I uploaded, and let me know if you find anything interesting! But my conclusion remains that this data doesn't reveal where you've been with any degree of accuracy.

Update: see my latest post where I conclude that this is data being downloaded from Apple, rather than uploaded, and that detailed history is not stored - thanks to Jude in the comment below for his suggestion about this.