Location Metadata Accuracy


Today’s Question: When I travel with my iPhone and take a photo with the intent of using the phone’s GPS feature to record my location, is it better to have WiFi turned on even if I am out of range of any WiFi router? As a corollary, how should I configure my settings when I am photographing abroad, in which case I usually turn off cellular data on my iPhone in order to avoid roaming charges?

Tim’s Quick Answer: Having all three receivers (cellular, WiFi, and GPS) enabled can help speed up the acquisition of more accurate location information that will be included in the metadata for your photos. I recommend turning of cellular data when traveling abroad without an activated cellular data plan, and keeping the phone in Airplane Mode except when want to quickly establish location metadata for a photo.

More Detail: In concept, you only need to have the GPS receiver enabled to obtain accurate location information for your photos. However, there are situations where you either aren’t able to achieve a good GPS signal quickly enough, or where you aren’t able to achieve a signal at all (such as when indoors). The cellular and WiFi antennas in the iPhone can help in these scenarios.

In general I prefer to have my iPhone set to Airplane Mode when traveling internationally, both to help preserve battery life and to avoid unintended cellular data charges. You can also turn off the Cellular Data option in the Cellular settings within the Settings app to help avoid cellular data charges.

I generally leave WiFi turned on, so that I can access WiFi networks more readily and so any nearby WiFi signals can be used to help the iPhone more quickly determine your location.

When I want to quickly ensure the location information on my iPhone is accurate, I will also temporarily turn off Airplane Mode so the cellular antenna is active. With the Cellular Data setting turned off this won’t risk any significant data charges. It will, however, generally provide the fastest location update if there is a cellular tower in range.

To confirm the accuracy of the current location information, I will either make sure I have cached map data when online, or use an app that enables you to view a map even when you don’t have a data connection (such as a navigation app you might use when driving).

What I often find is that my iPhone still thinks I am at a previous location, because it hasn’t yet acquired a signal to indicate a new location. Turning off Airplane Mode will enable a search for cellular networks, which is often the fastest way to update your location information. By watching your current location on a map using an appropriate app, you can confirm when you have an accurate location reference on the iPhone, so you can capture photos with the confidence that location metadata will be accurate.

Note, by the way, that the general concepts here apply to all smartphones, not just the iPhone. By capturing photos with a smartphone that will contain accurate location information, you can then use that information to help manage photos captured with other cameras that might not have a built-in GPS receiver.