A track is a series of points, and calculating its distance is relatively simple. Despite this, there may be disagreements in the calculation in different applications.
During an activity you may stay in one place for a while, to eat, take a picture or simply to take in some fresh air, for example. During these stops, the error inherent to the GPS system can generate points along the track as if you were moving slowly around that point. This can cause the track to build up distance that you haven’t actually travelled.
Land and TwoNav have a filter to keep this from happening and provide a more reliable distance calculation. It’s the “Minimum moving speed” parameter, which specifies the slowest speed at which you’re considered to be moving.
This parameter’s default value is 0.5 km/h. Any movement below this speed is regarded as noise and will not add to the distance.
In some cases, a track can have very low speeds at non-stopping points. In these cases, Land and TwoNav can give a faulty reading, since the distance in those segments with a speed below 0.5 km/h will not be added.
To get an accurate distance reading in these cases, you can do one of two things:
- Correct the speeds on the track: This will recalculate all the speeds on the track and thus correct for this effect.
- In Land: Right click on the track and ‘Tools > Assign time and speed’
- TwoNav 3 and 4: From the track properties, open the context menu and select ‘Edit > Assign time/speed’
- Modify the ‘Minimum moving speed’ parameter: If you set this parameter to 0, then low speeds will not be filtered out and the distance calculation will include tracks with irregular speeds.
- In Land: ‘Options > Tracks'
- In TwoNav 3: ‘Settings > Full settings > Advanced > Min. Moving Speed’
- In TwoNav 4: ‘Settings > Activity profiles > Activity recording > Min. Moving Speed'
Note: If this parameter’s value is different in Land and TwoNav, the distance calculation may differ in the two programs.