> For the USA, I don't know if you can look up that info anywhere.

I agree - so far I haven't found an open database of GSM tower locations in
the U.S. except for a couple user-contributed ones such as:
http://www.navizon.com/navizon_v-gps.asp which I doubt are accurate or
complete for all GSM service providers.

> If you're working in a limited area, some GSM devices can help
> you find cell locations for yourself. I have Siemens phones,
> and Wavecom and Falcom (Wavecom engine) modems which let me
> read TA (timing advance). This will give distance to the cell
> with an accuracy of about 550 metres. Do some intensive
> automated logging with GPS correlation from a moving device,
> and you can quickly build up a good picture of where the cells
> are.

In my case, however, I have to determine my geographic location
independently of GPS. All I need to do is to relate a GSM tower's cell ID
to a location very roughly. But even that rough tower location data seems
to be unavailable.

I assume a way around this would be to purchase an API from every service
provider, but this involves considerable expense, and there is no assurance
that all providers would be willing to do this.

So ONLY the network service providers can sell tower-based geo-location
services (ie - triangulation) because they alone have the tower location
data?

Henry