Waypoint and Courses

by old_man_biking

Downloads: 1,161 (12) • Reviews: 4

Version:

3.0.6010

Updated:

Jun 15, 2016

Correct for barometric drift

Correct for barometric drift

Postby texmurphy » Mon Apr 14, 2014 1:07 pm

I wanted to correct for barometric drift on an activity recorded with Edge 500 using 1 second recording with PM. However the plugin only says elevation present, should it be replaced? If I say "yes" then barometric elevation is replaced by DEM elevation which has the usual jagged bad elevation from a database. If I say "no" then the plugin reports a fault "Key not found" (see below).
Does the barometric elevation drift option work?
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Image1.jpg
unexpected exception caught
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Re: Correct for barometric drift

Postby old_man_biking » Tue Apr 15, 2014 2:16 am

Ouch, an error - obviously since the very beginning of the plugin.
Occurs whenever you answer a question "... already has elevation ... Do you want to overwrite ..." with "no".
--> workaround: don't say "no" :)
Will be fixed for the next version.

Thanks,
OMB
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Re: Correct for barometric drift

Postby texmurphy » Tue Apr 15, 2014 8:40 am

old_man_biking wrote:--> workaround: don't say "no" :)

But I want to correct barometric drift, not replace the elevation from the barometric altimeter.
Answer "Yes" gives me jagged, real bad elevations - worse then the Elevation Correction Plugin :evil:
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elevation.jpg
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Re: Correct for barometric drift

Postby old_man_biking » Tue Apr 15, 2014 9:17 am

I'm not sure if I understand you right - or if you understood my post right??

Add/fix elevation works like this:
1. check if there are already elevation data; if no proceed, if yes ask the user if s/he really wants to change these
2. if there are elevation data and the user wants to fix them, the plugin tries to decide between 2 cases:
A) elevation data comes from GPS (typically lots of spikes = "high frequent noise")
B) elevation data comes from barometric altimeter, which might have drifted
This happens automagically.
3. if the plugin detects case B) it asks you, if it shall remove the drift (i.e. superpose a verrryyy slowwwllly changing function to the original data).
4. if you consent, it does so; otherwise it simply REPLACES elevation data with DEM based one.

The error is induced by saying "no" at step 1 - not at step 3, what your latest post might assume.

Cheers,
OMB
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Re: Correct for barometric drift

Postby texmurphy » Tue Apr 15, 2014 9:46 am

I select Edit->Elevation->Add/Fix Elevation
Popup say activity already has elevation data, Do you really want to overwrite them?
If I say "Yes" then it overwrites - never does a drift fix for any activity tested.
So the A or B test always fails to the overwrite condition, never to barometric drift correct.

I never get to Step 3
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Re: Correct for barometric drift

Postby old_man_biking » Wed Apr 16, 2014 1:57 am

As I wrote before, step 2 (check for barometric drift) happens automagically.
Obviously the plugin hasn't detected any significant barometric drift for your activity/-ies.
If you're not convinced that the plugin is right in this case, please export the activity in .FITLOG format, zip and attach it to your post.
I'll have a look then.
Please add information which elevation data source(s) you've selected (e.g. screenshot of the Settings:Plugins:W&C page).
Cheers,
OMB
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Re: Correct for barometric drift

Postby texmurphy » Wed Apr 16, 2014 10:25 am

Example .fit and .fitlog sent via email where there is a 30ft barometric drift over 20 minutes on a roundtrip ride. Settings for W&C shown below.
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screenshot of the Settings:Plugins:W&C page
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Re: Correct for barometric drift

Postby old_man_biking » Thu Apr 17, 2014 3:30 am

I had tried to answer via email - however encountered problems. Please see my PM to you.
Cheers,
OMB
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