This is a nice informative set of posts on the issue. I especially like the code to check on the caching of location data, and I've bookmarked it so next time I work on some tracking software I have I can fix that particular problem.
I'm curious, have you run across a way to force filemaker to evaluate the location information using the direct GPS, rather than trying to use the wireless network first? My experience is that it always uses wireless first and this can be frustratingly slow, not to mention not terribly accurate.
I'm glad you liked the post! I have not run across a way to force FileMaker to skip checking WiFi and cell phone towers straight to just GPS.
Using wireless first doesn't make the location fix slower, though. Using WiFi base stations and cell phone towers is actually supposed to make it faster when only a less accurate fix is needed. GPS is far from instant, and only using GPS would make slower and less reliable — it's often better to have a 65m fix in 2 seconds vs. a 5m fix in 30 seconds or no fix at all. No matter what method is being used, there's a tradeoff between speed and accuracy — you can have a faster fix, or a more accurate one, but usually not both. This is reflected in the accuracy and timeout parameters accepted by the Location and LocationValues functions, which are the only control we have over this.