[skidooer]

The iPhone 3G and later have real GPS.

They use an A-GPS chip. The "A" in A-GPS stands for assisted, which means it can be assisted by the cell towers to help find the GPS satellites more quickly. Because of the connection with the cell network, some confuse its capabilities with plain triangulation. It will continue to function as a plain GPS device in the absence of cell service, however.

Most of the points on my map correspond exactly with known locations of my carrier's towers, so the explanation makes sense. However, there are dots in locations where there are no towers. I don't think it is WiFi locations because I do not see any of the places I commonly use WiFi.

[pudquick]

You don't need to connect to the network for it to be recorded.

The Skyhook-alike ( Apple rolled its own: http://blogs.wsj.com/digits/2010/07/30/skyhook-loses-a-big-f... ) tech works because your device is able to poll available wireless AP MACs, even if you don't sign into them or know the password. 802.11 headers have a MAC frame that's always broadcast in the clear.