The Magpi+ ("Magpi Plus") app, available for Android and iOS, has an improved interface for capturing GPS questions, including the ability to see a map of the current location, and to drag-and-drop the map pin to fine-tune the captured coordinates.
IMPORTANT NOTE REGARDING AIRPLANE MODE
Basic GPS is a satellite-based system, so using Airplane Mode (which turns off wifi and bluetooth and cellular) should not affect GPS. However, on some Android devices, turning on Airplane Mode can also make the GPS malfunction. If you are unable to use GPS questions while using Airplane Mode, turn Airplane Mode off and manually turn off bluetooth, wifi, etc.