Just relaxing after a hot day riding, walking and not much else.
I thought I would chip in.
Interesting observation from Frank, that a nobbled route transferred to a new XT returns i satus to imported. I'm not taking that bet. I'd lose ! I'd quite happily bu you a beer though.
Before you experiment with a tracktrip, (a track converted to a trip), can I suggest that you first load a track and select Go! I bet most people have never tried this but it is a most relaxing method of navigating. It tells you where your track is eg '3 miles over there' - pointing to the closest point as the crow flies.
Once you have played with that, you get an idea of what a tracktrip is doing. It does exactly the same thing, except it calculates a new section of route and superglues it to the original tracktrip at that closest point. The two joined sections now become the new tracktrip.
If you deviate from a track trip in such a way that the closest point is behind you, you will notice something very familiar. A RUT.
I believed two years ago that the RUT behaviour was caused by something in Basecamp making the XT think that it was a different type of route, and the only reason I could come up with was the subclass info. Frank and I had both looked into this possibility, but I tested routes with no subclass, with default subclass, altered subclass and normal. The results were inconclusive. But I still believed that somehow tracktrips and RUT. behaviour were linked - that when a route is recalculated, somehow the programmer had referenced the wrong subroutine.
The fact that Garmin call these tracktrips 'Trips', when they also call the things from Basecamp containing a start, end and a few route points, 'Trips'. .... well that added weight to my suspicion.
So. I think that a tack trip has to be distinguished from a standard point to point route, in some way. There are actually three kinds of routes. Those created by the XT. Those created in Basecamp and transferred to trip planner. Those created as tracks, imported and converted to Triptracks by the XT.
There's a fourth. Those tracks and routes created in Explore and cinverted into something navigable by the XT. This is similar to the third.
Problem is that standard Basecamp routes have been classed as imported and not saved. So when these get recalculated the behave like the triptracks.
I found a very definitive tell tale sign that the navigation is displaying RUT behaviour. Turn off U turns. Deviate and let it calculate a way to take you back by using side roads, laybys, housing estates etc. After it has done a couple of these, stop at the side of the road and look at the route that it is trying to get you to follow. It will contain all of those housing estate / sideroad / layby 'turn round' sections. Why, if it is calculating a new route would it do that?
The answer is that it isn't calculating a new route, it is suprgluing a new section to get you back to the closest point of the original. And that is behind you. And that is exactly what happens when you deviate from a tracktrip. There had to be one key difference that distinguished an XT route from an imported route. So I set about proving that an already tested RUT route would not display RUT behaviour using identical saved Waypoints, If the route was built in the XT.
And that was why I was so excited about that single byte change. It seems to be the single thing that makes the XT behave as if it is a tracktrip, and behave as if it was created as a normal route in trip planner.
And that was exactly what we were looking for. @Frankb found it. I'd already done the testing of various routes so that I knew when it would RUT and when it wouldn't
The observation that routes were divided into 'Imported' and 'Saved' was a revelation to me. Because I had been resetting my XT for every test, I never had both types loaded at the same time, so I'd never noticed it.
Info on tracktrips is in this section.
https://www.zumouserforums.co.uk/app.php/ZXT-P45