Author Topic: Weird thing with reversed tracklogs  (Read 1541 times)

Feanor

  • It's mostly downhill from here.
Weird thing with reversed tracklogs
« on: 26 May, 2022, 08:43:31 pm »
So Mrs F wanted a track to follow on her Garmin, to and from an event.

I have ridden this route many times, but usually in one direction, as part of a longer ride.
I grab my as-ridden tracklog, load it into Mapsource, crop it down, and save it as the outbound track.
I then use Mapsource to 'Reverse Track', and save it out again as a return track.

Upon import to her device, the outbound is fine, but the return is all messed up.
Distance and time shown on the screen are silly numbers.
Viewing it on the map shows a straight line from start to end.

Turns out the issue is that the original tracklog, because it was an as-ridden GPX, contains date/time stamps. Reversing it in Mapsource is quite literal: every trackpoint is re-ordered, including the date/time. Time runs in reverse in the reversed tracklog. This confuses the fuck out of the Garmin GPS when you try to import it.

Solution: Notepad++ and a regexp to strip the time/date tags.
All is well.


Re: Weird thing with reversed tracklogs
« Reply #1 on: 26 May, 2022, 10:52:17 pm »
Use Phil’s software then reverse it!