Statistics errors expecially with "altitude"

Hi Orux Team,
I noticed I often have errors in the statistics of the tracks, in particular with elevation gain/loss.

Oruxmaps says a value, while if I export the track as gpx file and I load it on others GPS viewer, I see different data.
I'm not talking about few meters... for example on the last track I created Oruxmaps says "elevation gain 1365m", while other gps viewer say ~ 1020m. Sometimes the error is much higher.
And Oruxmaps is the only one which reports such a different value, while all the others gps tools I tried report similar data.

This happens also with other statistical values, like average speed, but "altitude" is the worst.

Do I need to make some particular settings? Or am I doing something wrong?

Thanks,
Claudio:)

pelleoss wrote:Hi Orux Team,
I noticed I often have errors in the statistics of the tracks, in particular with elevation gain/loss.

Oruxmaps says a value, while if I export the track as gpx file and I load it on others GPS viewer, I see different data.
I'm not talking about few meters... for example on the last track I created Oruxmaps says "elevation gain 1365m", while other gps viewer say ~ 1020m. Sometimes the error is much higher.
And Oruxmaps is the only one which reports such a different value, while all the others gps tools I tried report similar data.

This happens also with other statistical values, like average speed, but "altitude" is the worst.

Do I need to make some particular settings? Or am I doing something wrong?

Thanks,
Claudio:)

Hi, Claudio;

It is a problem with gps and altitude accuracy.

OruxMaps uses a formula to soften the error, but it is impossible to remove.

I will increase the filter used, to soften even more the value.

Note that some programs again filter the track, or even correct it, using a digital terrain model. So when reloading you see different values.

I have plans to add the option of correcting the height with an online digital terrain model, to avoid using the height given by the GPS.

orux

I can confirm that there several errors in the statistics data given by OruxMaps in GPX exports.

• Start time given is about 6 minutes too early (very weird), while finish time is correct.
  
• Moving time is too short (at least when walking slowly).
  
• Max. Speed is 0.
  
• Minimum and Maximum altitude are exchanged.
  
• Rise speed, fall speed, Elevation gain and loss meanwhile look reasonable.
  

dvo wrote:I can confirm that there several errors in the statistics data given by OruxMaps in GPX exports.

• Start time given is about 6 minutes too early (very weird), while finish time is correct.
  
• Moving time is too short (at least when walking slowly).
  
• Max. Speed is 0.
  
• Minimum and Maximum altitude are exchanged.
  
• Rise speed, fall speed, Elevation gain and loss meanwhile look reasonable.
  

Hi;

Start time should be saved when you hit 'start logging' button. But if you have a device with a poor gps, it is possible that situation, because first gps position fix can be received xx minutes after.

OruxMaps sees no movement if the GPS indicates a speed below 0.25 m/s. The problem is that the gps (especially if they are of poor quality) may indicate higher speed even when you stand.

Max/Min altitude and max speed should be correct in next version.

here there is a beta-->http://www.oruxmaps.com/cs

orux

Hi orux,

thank you for your quick and constructive reply!

Start time should be saved when you hit 'start logging' button. But if you have a device with a poor gps, it is possible that situation, because first gps position fix can be received xx minutes after.

Oops, good point, I checked this and indeed if the GPS sensor already has a fix the start time is the same as the time of the first trackpoint.

OruxMaps sees no movement if the GPS indicates a speed below 0.25 m/s. The problem is that the gps (especially if they are of poor quality) may indicate higher speed even when you stand.

I understand, thanks for the explanation.

Max/Min altitude and max speed should be correct in next version.

here there is a beta-->http://www.oruxmaps.com/cs

Yes, using the latest beta version 4.1.20, everything looks good, so I'd say this bug can be closed :-)