It appears that Devonthink ToGo is constantly using the location services while the app is active. This will be a severe battery drain. The only time that the app should need to use the GPS is when creating a new note, or when I select the appropriate icon to view notes on the map.
Location Services are actually not a major drain on the battery. If you use any of the navigation apps for the iPhone, you will note that they can be used for hours without a major drop in battery capacity. We enable location services while DTTG is running as it is difficult to determine just when we might need to get your location. Latency in determining location would either make you wait for a map to appear, or make your new documents unavailable while we are figuring out where you are. I should point out that most location-based applications now enable this service for the entire time the application is running, without causing undue effects on battery usage.
Enabling WiFi drains your battery far more than any other service on the iPhone. You might want to consider this if you are finding severe issues with battery time on your phone. If you do find that DTTG is draining your battery unnecessarily (with WiFi turned off), then please let us know via the forum or by filing a bug report.
I can’t speak for the specific way in which you use location services, however as a general statement, this is simply not true. In fact, it’s so not true that “minimize use of location services” is the first recommendation on Apple’s list for saving battery life (c.f. http://www.apple.com/batteries/iphone.html). My personal experience has been that running the built-in maps application with continuous updating has an enormous impact on battery life. Like 50%. It’s certainly possible that that effect is due to something else (e.g. the maps rendering), but again – Apple claims otherwise.
This simply isn’t true. I have tons of apps that utilize location (DT is not “location-based”, per se, like a GPS program.) NONE of them keep location services on all of the time (see OmniFocus, for instance, which has features to sort To-Do list items by distance to where you need to be to do them). DTTGO is the only app that I’ve seen that does this.
I guarantee that WiFi is not worse than WiFi+location services. Using MORE battery doesn’t make the situation better.
Overall, I understand that this may be much ado about nothing, but you have to realize that people instantly noticed this because, contrary to what you say, in my experience it is extremely unusual to leave location services on continuously AND we’ve been taught by Apple to worry about it.
Thanks for bringing DTTGO to market. It’s been much anticipated.
If your claims to the contrary of what Apple feeds us consumers is based on your own objective testing of the App, please let us know. Otherwise please consider changing the app to be more inline with what we see with other applications.
weisen nailed it… GPS is an enormous drain on the battery. In my experience, 24 hours of battery life with a fair amount of standby time turns into 3 or 4 hours. Even when the phone is in standby, the GPS radio is active. This also causes the phone to warm up. This isn’t an issue if I press the home button before the power button, but how often do you do that? When I’m done with whatever I was doing, I simply press the button on the top of the phone while I slide it back into my pocket.
OmniFocus was also my point of reference for how this should work, but Evernote can also be exemplified. The location services only become active once I start creating a new note.