Category Archives: Track and sensors

MyTrails records zigzag around my track

This means your GPS signal is noisy, which may be:

  • because your GPS module is not very sensitive or misconfigured
  • because of the terrain (in thick woods or canyons)
  • because it’s stored at the bottom of a backpack or pocket
  • because of jamming (intentional or power lines)

Once you’ve excluded the physical causes and have reset your GPS (and rebooted the phone for good measure), if the track is still showing zigzags, you can set up filtering in MyTrails by using the set kalman filter n hidden option, where n is the approximate nominal speed in m/s, for example 1 for walking, 8 for cycling.

How can I transfer GPX tracks to my computer?

MyTrails store the GPX files for tracks you have recorded in /sdcard/MyTrails/gpx (you can change this in MyTrails > Preferences > Other).

Here are a few methods you can use to transfer track files:

  • the most basic method for transferring files is to connect your device to the computer via USB (make sure to set the USB transfer mode to MTP, and on Mac use Google’s Android File Transfer to copy the files over). More info here.
  • another method is to use a file manager on Android to copy the files to a physical SD card (if you have one and can plug it into your device) and then read the SD card on the computer
  • MyTrails Pro has built-in support for saving tracks to Dropbox (or a track-sharing community such as GPSies); if you also use Dropbox on your computer, the file will magically appear there
  • finally, in MyTrails’ Track Manager, you can long-tap a track and use the Share menu to send the file via email or another app that is capable of sharing files

Cumulated climb or descent

Dénivelé

In order to calculate the cumulated altitude differential, MyTrails must identify parts of the altitude curve where the track switches from uphill to downhill or vice versa. Because altitude measurements are not exact (especially from the GPS), MyTrails uses a filter to attempt to differentiate measurement errors from actual changes in the track.

Different applications use different filters, which may yield very different altitude differentials.

You will get better results when using altimeter-derived altitudes, or after applying altitude normalization (when saving the track, or in the Track Manager).

In MyTrails 2.0.11 and later, you can additionally use two options in Preferences > Sensors: Altitude stabilization (which performs some filtering on GPS altitude data to reduce the noise) and Cumulative climb filter, which you can set higher to avoid MyTrails overestimating cumulative climb when the GPS data is very noisy.

New recording UI

MyTrails 2.0.9 introduces a new recording UI, which should make it easier for new users to grasp what the application is doing. The original recording UI is still available and will continue to be supported for users who prefer a greater degree of control.

How to select

You can select the type of recording UI in MyTrails > Preferences > Recording, Extended recording UI (uncheck for the new UI).

How does the new recording system work?

The new system consists of two buttons: Record/Pause and Stop.

New recording UI

Currently recording

The icon that is lit corresponds to the current recording state. Tap a button to switch to that state. For example, to pause the recording (without saving and closing the track), tap Record/Pause.

Tap the Stop button when you are done with your recording: MyTrails asks you to save the track (providing a name, etc.), and possibly upload the track to a community. The recording is then cleared, so MyTrails is ready for another recording, which you can do immediately by hitting the Record button.

You can also find the recording controls in the navigation menu, which is available on all main screens (stats, graphs, tracks, maps, etc.), not just the map view.

Streamlining the recording experience

With this new mode, MyTrails tries to make it very quick and easy to record your tracks:

  • when you launch MyTrails, recording starts right away (unless MyTrails was exited in the paused state)
  • when you get back to your starting point, MyTrails reminds you to save the recording with an unobtrusive notification (you can dismiss it by swiping it away; you can also disable this feature)
  • when you stop the recording and save the track, you can leave MyTrails any way you like:
    • just sending MyTrails to the background (using the Home button) stops using the GPS
    • actually quitting (using the Back button) is still better: when you next start it, MyTrails will know to start recording a new track

MyTrails is always looking for a GPS signal – AKA how can I stop MyTrails?

MyTrails can record your track whether it’s visible or running in the background. Even if you’re not recording a track, MyTrails may use the GPS if you have the proximity notifications option turned on.

When you want to stop using MyTrails, you should quit it like any other application (including Google Maps), by using the back key or button. When you do this, MyTrails asks you whether you want to keep recording the track in the background. Answer ‘no’ to stop MyTrails entirely.

Back button

Back button

Back key

Back key

Note that MyTrails doesn’t ask about quitting if you have already paused track recording. You can also use the Pause button in the recording notification to stop recording.

Recording notification

Recording notification

If you find this confusing, you can enable a Quit option to the navigation menu in MyTrails > Preferences > Other.

Compass calibration

MyTrails can use your phone’s built-in magnetometer and accelerometer to simulate a compass. However, unlike a physical compass, phones need to be periodically calibrated to provide an accurate reading of the magnetic north bearing.

There are two methods (both need MyTrails to be running with the screen on – MyTrails disables the compass when the screen is off):

Keep in mind that even after calibration, the compass is sensitive to interference: don’t place it next to ferrous metals.

Unlike a physical compass, MyTrails can automatically correct the magnetic declination to provide a reading of the geographic rather than magnetic north.

If the compass seems to rotate in the opposite direction of your real movement when you, please try using the toggle reverse compass hidden option.

In addition to the compass, MyTrails can use the GPS-derived heading, with the following caveats: it’s only active above 1m/s (too imprecise at slower speeds), and the GPS heading indicates the direction of your travel, not the direction the phone’s screen is pointing.

Another method, described by Google.

MyTrails incorrectly computes distance and speed

MyTrails uses built-in Android methods to compute distances (and speeds). Unfortunately a small number of phones use a version of Android where a critical element of the platform (the Dalvik JIT compiler) suffers from a bug that causes these calculations to be severely incorrect.

This issue may also cause tracks to be displayed as thick lines across the screen.

In MyTrails 2.0 and later, please try to activate the Fallback distance calculation preference in Visual preferences.

In MyTrails 1.3.23 and later, you can work around this problem by using the toggle alternate distance hidden option.