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OS Locate FAQs

iOS and Android Grid Ref location app

The location shown relies on information from the hardware in the phone/tablet. GPS works best with a clear view of the sky. The accuracy will depend on your device and local conditions, and will generally improve if you remain still for a few moments. We only show six-figure grid references as this is accurate as most phone GPS chips will support. GPS location is normally around 15m accuracy in good conditions.

Most smartphones, when unable to get an accurate GPS location will show the best guess. This may often be the location of the nearest mobile phone tower, so could be several kilometres away. The location shown will sometimes jump around as your device calculates a more accurate position.

The compass relies on the hardware in the phone/tablet. In our tests with various devices, they are mostly accurate to within a few degrees, once calibrated. Unlike traditional compasses, your phone compass will need regular calibration - usually each day or two . If your device does not have a built in compass calibration, slowly rotating the phone through 360 degress while holding it flat can help get a more accurate reading.

Nearby magnets, such as jacket poppers, some metals and electric fields will effect your compass, so keep it away from these while in use.

OS Locate points to True North (towards the geographic North Pole). True North is different from Grid North in Britain by up to 6° (but they are the same along the line of longitude 2° West).

If you require accurate compass bearings, we do not recommend using the phone’s internal compass, but instead use a dedicated compass.

Height taken from the GPS signal is less accurate than location, so is normally +/-50m. If you have a data connection, we will look up the height from your current location, giving a height accurate to 5m for most of Great Britain.

For maximum GPS location accuracy:

  • Have a clear view of the sky, and be avoid being close to tall buildings or cliffs.
  • Stay still. Especially if your device has been recently rebooted or location turned on, it can take a minute or so to get a fix, and remaining still speeds this up. When switching back to the app, it can take 10 to 20 seconds to reestablish location
  • Some phone cases may interfere with your ability to get a good GPS signal. Try with and without to see if there is a difference.
  • Always compare the map location given by the Grid Ref to visible features. If they do not seem to match, check location again or check you have got the correct map location

Some devices do not have a magnetic compass, so you will be unable to use this feature. Use a traditional compass, or move a short distance in one direction and note the change in Grid Ref to work out your bearing.

These can be changed in the “About” then “settings” menu at any time.

Read all about how to use a grid ref here: GetOutside: Beginners Guide to Grid References.

Yes, only the messaging functions need a mobile signal. Height accuracy is increased with a data signal available, but an approximation will be used when offline.

Only the Latitude and Longitude readings will be valid overseas. When using the app in Great Britain you can select the National Grid section in Settings.

The legal section inbuilt to the app explains that the licence granted is for personal, non-commercial use.

Any app which uses location services on your phone will increase battery use. Turn off location services when not needed to conserve power, but be aware GPS can take a period of time to re-establish an accurate location when you turn it back on. Newer phones will automatically turn location services off when the app is in the background or the screen is off. After turning back on or bringing the app back to the front, it may take 10 or 20 seconds or so to get an accurate location.