Merge tracks creates errant trackpoints?

Started by 11elevenths, April 22, 2022, 15:14:21

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Menion

Hello, thanks for the detailed video.

May you please export all three routes to the GPX file and share it with me? If I understand correctly, I have no idea why this happens so I'll gladly look at it. Just needs data to simulate this issue. Thanks
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11elevenths

I just made another test just to be sure this was consistently happening
I created a route
then added 2 splits so now we have parts A, B, C
then turned off the middle part B
then drew another track connecting A and C called B_new
then merged A, B_new, C
the same extra trackpoint error happened only on the 2nd merge point???

anyhow...attached are the 4 gpx tracks used in the video.  Maybe you can figure out why it is happening...since it is not a large distance in the 1-3 extra tracepoints it is not bad to deal with.  Maybe there is a rounding filter that can be added when merging to force it to attach the tracks clean?

thanks

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0709

#3
The attached tracks do consist out of multiple tracksegments.

By Topografix gpx 1.1 (http://www.topografix.com)

A Track Segment holds a list of Track Points which are logically connected in order.
To represent a single GPS track where GPS reception was lost, or the GPS receiver was turned off, start a new Track Segment for each continuous span of track data.

There are two common approaches to deal (display) a GPX track with multiple track segments:

1. DISPLAY.
- By Plotaroute, RWGPS, RTWtool, Garmin programs
- Ignore it so just connect the segments and show as a single track.
- Not correct imo as otherwise tracksegments had not te be invented.
   
2. DISPLAY.
- By Locus, Gpx editor, Gps Visualizer, Gps Prune, Gps Track Editor, GpXSee, Google Earth(kml), B_router web MyGPSFiles, gpxeditor.co.uk,
-  Show a gap between segments, so it does look like different tracks
-  All points inside a segment are drawn as one continous line..
-  A single track however can contain out of multiple segments.

Does the gap bother you visually? Functionally anyway, it just remains one track with some fully transparent straight connecting lines between the track segments. 
"You" can also 'stitch' them together in a slightly different way so that there is no visual gap in actual Locus and other apps.
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11elevenths

Thanks 0709 for your response.  That is interesting and beyond my understanding by I'm trying.

I do not believe I need anything other than locus to do this surgery on tracks ie remove and insert parts and what I see should be what I get but this error happens with gaps and without.

Does it really bother me... not really but I know the locus team would like to know what it is.  Try it yourself on your own system with 4x I have been able to make it happen twice.

Caltopo and some of the programs you listed can merge tracks clean.
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11elevenths

In my reply #2 above I meant merge A, new_B , C.

I will try this programs to see the individual track points better... maybe the errors are in the gpx but do not display???

All these were made using the routing tool and were not recorded.
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11elevenths

0709...sorry did not see the 2 attachments when replying before on my phone.  When examining the htm it does show both errors still.

Locus can sew them together with a gap or without but the errors I am seeing remain regardless.
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Menion

Thanks for the extra info. Weird,

- I was trying to import the GPX files you shared with me (thanks for it), but I'm unable to find out how they belong together as the two tracks seem to be quite identical ...

- so I tried based on your description, to simulate it on my own route, but no success so far. There really should be some issue in the app because of "breaks" as @0709 wrote. Just needs to find out the exact steps. I'll be watching it.
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0709

#8
Thanks for the screenshots.
I hadn't really understood the actual question that well in your long video with your own local [EN] version.
My hearing is already not as optimal as it once was, and I do speak a mother tongue other than EN(US)
Basic [EN] with very good articulation as the school teacher(s) may teach it can just about do it ;-)

The screenshots.
If the source material you are going to cut and weld is not 100% exactly the same, so  you will see this in the result.

So first you took a piece away from the original track, the path that runs along the lake.
Then you designed a new part of the track which will run along that highway.  Correct?

This newly designed segment will then be placed in the empty "hole". At the welding places you will see small deviations.
It doesn't bother me at all....but admittedly it is not the perfection that you apparently expect here.
However, since there is no new complete track routing, these small deviations are not corrected.
Welding tracks together is a surgical job that you need to do partly manually and quite precisely.
I don't want to start such a complex and lengthy "welding" process. This example convinces me even more.

Imo you can more comfortably just redesign the whole trajectory through (a) new B_router routing.
By means of a retrace function where you place the original tracks as a reference template in the background.

Translated with www.DeepL.com/Translator (free version)
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11elevenths

***SOLVED***

This is human error...(ME)!

I did another test and really zoomed in where I clicked down to draw the new inner segment and made sure I was exactly on the road when beginning the new route.  The original errors I got must have been because I was zoomed out and I had not clicked exactly on the road bounds and been slightly off the road causing the extra track points.  Sorry for wasting everyone's time...delete this thread please and put me in the penalty box.
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0709

Quoteput me in the penalty box.
I'm sorry, all seats are full. New bookings will be refused.  ::)
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