Yep, it would be a huge job to map (and then keep updated) the towers
ourselves because we need to be operable throughout the U.S. But thank you
for all the good info, John. I've learned a lot!

Henry


"John Henderson" <jhenRemoveThis@talk21.com> wrote in message
news:67k4b0F2omag7U1@mid.individual.net...
> Henry VIII wrote:
>
>> 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 was thinking that you might be able to map the locations for
> yourself as a separate exercise, prior to your implementing
> your proposed main system. This would involve writing an
> additional purpose-built application to initially correlate
> GPS, cell ID and TA data as a foundation for the real
> application.
>
> How feasible this is would depend on the geographical area you
> want to cover. Obviously, covering a significant part of a
> country the size of the US in this way would be completely out
> of the question (except for a large organization like google).
>
>> 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?
>
> I agree that the secrecy is likely motivated by purely
> commercial concerns.
>
> John