Where the F**k Was I by James Bridle, based on his iPhone geodata, self-published in 2011.
"....digital memory sits somewhere between experience and non-experience; it is also an approximation; it is also a lie. These location records do not show where I was, but an approximation based on the device’s own idea of place, its own way of seeing. They cross-reference me with digital infrastructure, with cell towers and wireless networks, with points created by others in its database. Where I correlate location with physical landmarks, friends and personal experiences, the algorithms latch onto invisible, virtual spaces, and the extant memories of strangers."
Read the blog post on what it's all about.
You can buy the book here if you want.