track filter request - Maximum speed, same location...

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track filter request - Maximum speed, same location...

Steve Enns

 

My Garmin GPS will log occasionally log bad track data (when reestablishing reception typically).  (I don’t know if this occurs with other GPS manufactures or models.)   The errors can be fixed manually by viewing the track in mapsource (or other) by:

 

1)      Deleting track points with the same position as previous point and then,

2)      Deleting the track points that have an “impossible” speed (as calculated and displayed by mapsource. )

 

Therefore, I suggest and request ;-) additional track filters as follows:

 

1)      Filter track points where position has not changed.

2)      Filter track points where (synthesized) speed is above specified threshold value (default perhaps 800mph or 1287kmh)

 

(Sample .gpx track excerpt below with several track points with duplicate locations, then a jump at “impossible” (2400kmh) speed.)

 

Thanks for GPSBabel,

               Steve

 

     <trkpt lat="10.015904987230897" lon="-84.610755024477839">

        <ele>346.69262700000002</ele>

        <time>2007-01-19T01:12:17Z</time>

      </trkpt>

      <trkpt lat="10.015883026644588" lon="-84.610755024477839">

        <ele>347.653931</ele>

        <time>2007-01-19T01:33:07Z</time>

      </trkpt>

      <trkpt lat="10.015861988067627" lon="-84.610755024477839">

        <ele>347.653931</ele>

        <time>2007-01-19T01:33:15Z</time>

      </trkpt>

      <trkpt lat="10.015861988067627" lon="-84.610755024477839">

        <ele>356.30578600000001</ele>

        <time>2007-01-19T16:07:33Z</time>

      </trkpt>

      <trkpt lat="10.015861988067627" lon="-84.610755024477839">

        <ele>912.42846699999996</ele>

        <time>2007-01-19T16:07:34Z</time>

      </trkpt>

      <trkpt lat="10.015861988067627" lon="-84.610755024477839">

        <ele>911.94799799999998</ele>

        <time>2007-01-19T16:07:35Z</time>

      </trkpt>

      <trkpt lat="10.015861988067627" lon="-84.610755024477839">

        <ele>913.38989300000003</ele>

        <time>2007-01-19T16:08:10Z</time>

      </trkpt>

      <trkpt lat="10.022471034899354" lon="-84.215955985710025">

        <ele>913.38989300000003</ele>

        <time>2007-01-19T16:09:07Z</time>

      </trkpt>

      <trkpt lat="10.019810032099485" lon="-84.214196037501097">

        <ele>917.71557600000006</ele>

        <time>2007-01-19T16:09:36Z</time>

      </trkpt>

      <trkpt lat="10.019810032099485" lon="-84.214196037501097">

        <ele>921.56079099999999</ele>

        <time>2007-01-19T16:09:38Z</time>

      </trkpt>

      <trkpt lat="10.019810032099485" lon="-84.214196037501097">

        <ele>923.964111</ele>

        <time>2007-01-19T16:09:40Z</time>

      </trkpt>

      <trkpt lat="10.019788993522525" lon="-84.214174998924136">

        <ele>927.80957000000001</ele>

        <time>2007-01-19T16:09:43Z</time>

      </trkpt>


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Re: track filter request - Maximum speed, same location...

Robert Lipe-4


On Sat, Mar 14, 2015 at 6:35 PM, Steve Enns <[hidden email]> wrote:

 

My Garmin GPS will log occasionally log bad track data (when reestablishing reception typically).  (I don’t know if this occurs with other GPS manufactures or models.)   The errors can be fixed manually by viewing the track in mapsource (or other) by:

 

1)      Deleting track points with the same position as previous point and then,

2)      Deleting the track points that have an “impossible” speed (as calculated and displayed by mapsource. )


Several of the Garmin models create goofy tracks.  Tweaking your settings based on distance instead of time will help the first as it'll prevent it from dropping points when you're at a stop light or on a water break.

 

 Therefore, I suggest and request ;-) additional track filters as follows:

 

1)      Filter track points where position has not changed.

2)      Filter track points where (synthesized) speed is above specified threshold value (default perhaps 800mph or 1287kmh

That's the sdistance option in http://www.gpsbabel.org/htmldoc-development/filter_track.html


But categorically, the speed option doesn't work for most of the really stupid things that Garmin does.  When they basically lose lock and generate a bogus insta-travel in your bike ride when you went through a tunnel, they'll getnerate a 1000mph trip to Cuba (or whatever), drop a few points there, and then zing you back to your trail.  Only the first and last will have the really bogus speeds.

 

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by Intel and developed in partnership with Slashdot Media, is your hub for all
things parallel software development, from weekly thought leadership blogs to
news, videos, case studies, tutorials and more. Take a look and join the
conversation now. http://goparallel.sourceforge.net/
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