GPS issues

Your GPS location might not be available, or might be slow to obtain, for a number of reasons. These can be related to your phone’s general settings, settings on the NZTopo50 app, or to environmental or hardware factors.

You might also observe track recordings that don’t appear to show your true progress, only recording periodic points that show up as a series of jagged lines, or sometime adding points even when you are standing still.

Check through all the following options to see what might be the issue, and for tips on obtaining good location accuracy.

GPS settings on the NZTopo50 app

To display your GPS location on the map you will need to turn on GPS positioning in the app – simply tap the satellite icon at the bottom left of the screen. GPS positioning will also turn on if you start recording a track.

GPS on/off button. Green is on.

To see your GPS location you will need to allow the NZTopo50 app to have access to your location. When you first activate GPS positioning you will get a prompt to give this permission. Depending on your operating system you may have several options including to allow the access, allow it only once, or to deny permission.

To check your current permission settings you can either use your phones ‘Settings’ app, or check on the settings page in the NZTopo50 app itself. On the Apple version look under map controls for ‘location status’, or in the Android version under ‘Permissions’.

It is also worth noting that some devices do not actually have a GPS chip in them and cannot measure your GPS location. This may not be immediately obvious as the device can still estimate its location in urban areas using cellular and wifi signals, but you will not be able to determine your location as soon as you are off-line or outside of cellular range. It is however possible to use external plug in GPS devices with most phones/tablets if you really need GPS measurements.

Accuracy filter. On the settings page of the NZTopo50 app there is an option for filtering our inaccurate signals in a track recording. This can be useful to avoid poor quality signals being including in the recorded track, but can also result in very few points being recorded if signal accuracy is low and the filter setting is set too low. If you find that your track recordings show jagged lines with most of the track details missing then check that this filter setting is not set too low.

System settings

(1) Master Location Access. It is possible for you to turn off access to your location in a number of ways which will result in the NZTopo50 app (and all other apps) not being able to determine your position at all.

On an iPhone you can do this from the Settings App, under Privacy, Location Services. Toggle the switch to turn on/off location access on your phone. Further down the same page you can also check and adjust the individual access permissions for all of your installed apps. For This is done Main on/off location settings. For proper functioning of the NZTopo50 app make sure that Location Services is on, and that the NZTopo50 app settings displays ‘While Using’ (or ‘Always’).

On an Android phone, location access on your phone can be turned on/off from the Quick Settings panel (swipe down from top of screen, depending on Android version) using the ‘Location’ icon, or from the Settings App under Location. For full functionality of the NZTopo50 app, make sure that ‘Location’ is On and that under App Permissions the NZTopo50 app is listed under ‘Allowed all the time’, or ‘Allowed while in use’.

(2) Power Saving Modes. On Android phones, power saving settings can interfere with proper location access. Power saving modes will generally deactivate GPS positioning, so should be switched off if/when you want full functionality of the NZTopo50 app. This is a common cause of the ‘jagged line’ track recording where only a few datapoint are obtained, or sometimes none at all.

Anything that includes options like ‘Power Saving Mode’, ‘Battery Management’, or third party power saving apps should be disabled.

Power Saving settings vary with Android version and Phone model, but some examples are given below. For other versions or phones you should be able to find instructions by searching for your phone model and ‘disable power saving’.

  1. HTC: Settings > Power > Battery optimization > Not optimized > All apps > NZTopo50 > Don’t optimize > Done.
  2. Huawei:
    1. Turn Energy Settings to Normal and add NZTopo50 to “Protected Apps.”
    2. Settings > Apps > Advanced > Ignore optimizations > Allowed > All apps > NZTopo50 > Allow.
  3. LG: Settings > Battery & power saving > Battery usage > Ignore optimizations > turn ON for NZTopo50.
  4. Motorola: Settings > Battery > select the menu in the upper right-hand corner > Battery optimization > Not optimized > All Apps > NZTopo50 > Don’t Optimize.
  5. OnePlus (using OxygenOS Settings): Settings > Battery > Battery optimization > select menu at the top > switch to All apps list > NZTopo50 > Don’t optimize.
  6. Samsung: Settings > Apps > select the menu in the upper right-hand corner > Special access > Optimize battery usage > All apps > Toggle OFF for NZTopo50.
  7. Sony: Settings > Battery > select the menu in the upper right-hand corner > Battery optimization > Apps > NZTopo50.
  8. Xiaomi (MIUI OS): 
    1. Settings > Additional Settings > Battery & performance > Manage apps battery usage > apps > NZTopo50.
    2. Settings > Additional Settings > Privacy > Location > ensure you are using High Accuracy for Location Mode and allowing location access.

Also check, for some phone models, that Location is set to High Accuracy from the Settings App, under Connections, Location, Locating Method, High Accuracy.

Environmental factors

GPS signals are relatively weak signals and can be distorted or blocked by overhead or surrounding objects, or even by adverse weather conditions. This can affect both accuracy and availability. GPS satellites are also non-uniformly distributed in the sky and at different times the combination of available satellites may give an inferior signal (particularly in NZ which is of lower interest for satellite coverage and satellites tend to be concentrated lower on the horizon rather than overhead). For best location accuracy try to avoid heavy overhead cover or objects that block line of sight to the sky and horizon, avoid use of thick or metallic phone covers, and avoid burying your phone deep under other equipment.

Sometimes you may observe that it takes a long time to obtain an initial GPS location (or GPS ‘lock’), particularly when out of cell phone range or with wifi turned off (eg in flight mode). This is normal but can be exacerbated by poor signal conditions or by not having a recent approximate location reading. Once a ‘lock’ is obtained then measurements should be accurate and rapid as long as good signal conditions are maintained. If you wish to record a track and have an accurate start time or position then it is a good idea to switch on GPS in the app in advance to give your device time to obtain a GPS lock.

Trouble Shooting

Try toggling Location access on and off again (see above under System Settings)

Try restarting your phone (power off, on again)

Find an open spot with clear access to the sky and wait 10-15 minutes to see if an accurate GPS location is obtained.

Check other location apps to see if there is a difference in behaviour.