We’ve got complain from one customer of our geotagging solution Geotag Photos for iPhone. He was using our iPhone application abroad with roaming data off – and he was unable to get GPS location using Geotag Photos. We got also one similar negative review from another customer (we were sorry, that he didn’t wrote to us – it is always better to send us email, because we are reading emails every day and we can reply to email – not to reviews in AppStore) with similar problem.
But – I personally tested Geotag Photos on my vacation in Germany and France 2 weeks ago – sure I had roaming data off (what the hell is pricing data roaming in Europe?) and it worked perfectly. I guessed, that our customers are not the only ones, that have similar problems and I was right. Fortunately, there is solution for this.
It is necessary to understand, how GPS in iPhone is working. GPS chip is always counting with latest known location – it can predict from it, where to find satellites, so that it is relatively easy/fast to get current position. With iPhone, even when you move significantly (like 1000’s of miles), so called Assisted GPS can speed up to get current position as well – it is using network database and can get satellite positions though network. But in one case has GPS chip really hard work – when you move for half of Earth and have data roaming off (of course, our dear mobile operators). Then it can take 5-15 minutes to get first position.
Best way, how to do this is to start iPhone Maps application and even when you don’t have data, so that map will not be loaded, you can check for current position. Be in open area with good visibility to sky and please wait to get accurate enough position. You have to do this only once. Then clever iPhone will remember, that you’ve moved from Asia to Europe or vice-versa and in the next time, when you will want to use location services, it will take usual time (usually up to minute).