What Is This Purple Arrow on My iPhone?
The purple arrow icon on an iPhone indicates that the device is using the location services feature, which allows certain programs to track the location of your iPhone via GPS, cellular network data and Wi-Fi information. Many official and third-party apps use location services, including Camera and Compass. Though these programs are convenient, keeping them on all the time can drain your battery.
Several iPhone apps make use of your location data, such as the official Maps app. This app lets you track your location and look at a map and/or Google Street View of your surrounding area. Other programs that rely on location services include FourSquare and various exercise-related apps. Every app installed on your iPhone that uses location services is listed under the Location Services settings window.
The location services arrow appears in your status bar, next to the battery life indicator at the top of the screen. It resembles a purple indented triangle pointer, pointing up and to the right. It only appears when your iPhone is uploading location data.
Advantages/Disadvantages of Location Services
If you are using an app with location services, you can upload that data automatically, without any additional input. However, the data transmission can drain your battery and counts as data usage by some data plans. In addition, ensure that you trust the app that is using your uploaded location data, for the sake of privacy. App data collected through location services does not identify you unless you give the app using the data extra information.
Turning Off Location Services
You can disable location services under your iPhone Settings menu. Go to the general settings, choose "Location Services," and then turn off all location services. This will stop the arrow from showing up and also keep your location data secure. The downside is that you will not be able to access the Maps app or other apps that require your location data to function. As an alternative, with iOS 4 and up, you can selectively disable location services for certain apps, using the same menu options.