iPod Touch, Location Services, how?

I recently installed OffMaps, on my iPod Touch. OffMaps is an app that lets one download maps (it uses OpenStreetMap data) onto the device. I planned to use it simply as a way to carry a map of Montreal with me to use on my walks.

It has a “locate me” button, and it was able to locate me while I was home, in range of my home wifi. Makes sense. I know that the iPod Touch/iPhone make use of Skyhook Wireless technology that can use surrounding wifi signals for location. What surprised me was the “locate me” generally worked on my walk, away from my wifi hotspot.

I understand that the location technology makes passive use of surrounding wifi signals, and then through a database lookup is able to translate this into a latitude/longitude.

On an iPhone this lookup can be done via the data connection. My question is how this lookup can occur on an iPod touch, where there is no data connection?

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