Weird Routing Behaviour - Major Success.

[jfheath]

That is brilliant @FrankB

Let me get this straight. You tested a route that got you into a RUT.
You came back, took the same route, changed a byte in the file to flag it as Saved
Travelled the route again and it behaved perfectly.

Let me go back to the first step. Did you have to do anything to make it enter into a RUT. I normally have to skip a route point and then deviate - usually after passing another route point (but I just do that, I'm not sure it is necessary).

There may be other ways of getting into a RUT.

How do you know that you were stuck in a RUT - I mean the route I took on Thursday kept demanding that I go back, but that is becasue it was the fastest way to get to me end point. The key thing was the 'half way point' where to continue the way I was going was faster than going back.

The route created on BAsecamp didn't change its mind - and I proved (by turning off recalc) that it was making no attempt to take me tot he next route point, but that it was taking me back to the last point where it has told me to go back. It was laying a breadcrumb trail.

The route created on the XT did not do that. I knew where the halfway point was - the point where if I position the bike slightly east and set the destination it navigates in one direction and if I set it slightly west it chooses a route in the other direction. In fact it didn't wait until I reached the half way point before naviagting me ahead. It worked that out as soon as I was on the road leading to the half way point. About 3 miles early.

Next question - can we be sure that it wasn't affected by your personal travel history ? !!


This is lending weight to my unproven theory that a route that gets into a RUT is behaving like a track that has been converted to a Trip - in that deviation from the plot results in it heading for the closest point of the original. And with a route, that is behind you !

John

[FrankB]

@jfheath

Let me start by repeating: I will have to do so more testing, to be absolutely sure.
But the result was so surprisingly good that I did not want to wait any longer to post.

Now to your questions:

- It is the same route as the one I used in Januari-Februari when I tested about 8 different things and only one (1) behaved perfectly. (The perfect route was the one I created on the XT) We concluded back then that it was RUT.
- I must admit there is something different about today's test, and that is that I can not drive the same road, because of the fact that that road is blocked. But this road block caused even more deviation from the original route, so I still believe it was a good test. So I need to figure out a slightly different route that will get me into a RUT.
- But all things we observed back then are not present now. 1) No broken tracklog 2) no phantom via point 3) Only 1-3 U-turn request, and then recalculate to destination.
- I cleared my travel history before I began.

If you want I can give you detailed instructions on how to modify a trip, or even send you a small program that does this. That way you can conduct your own tests.

[danham]

@FrankB,

First of all, thank you for the incredible work and thought you have put into this. Very impressive.

I agree that not everyone will want to dive into a hex editor to ensure good navigation (though I'm tempted for an upcoming long trip). So we should look for another way to fool the XT into thinking a route created in BC is a Saved Trip. I don't have any ideas on that, but will think about it.

What OSes will your conversion program run under (I'm a Mac guy)?

-dan

[jfheath]

I got the HxD editor - in fact I downloaded it last time just before my brain went fuzzy for a period. I couldn't be bothered to do anything for a few weeks - which is why I wasn't bothered so much when tech support went silent for a while after Christmas.

I'm just trying to work out how the numbers are coded. Without success so far, so I'll take a look and see if they are likely to be pointers to where the number is actually stored.

But yes please send what you have. I like a puzzle, but I also have the opportunity to ride one of my other well tested RUT routes tomorrow, so it would be nice to load that in again and edit it. See what it does.

[Peobody]

@FrankB, identifying that byte is remarkable. I tested the bit change on one of my routes while sitting in a hotel room waiting for the heavy rain to subside. It is now listed as Saved instead of Imported. I am watching this discussion with great interest in the hopes that further testing confirms your theory and then that someone at Garmin will react appropriately.

[FrankB]

What OSes will your conversion program run under (I'm a Mac guy)?

If I have to write something quickly, as I did now, I code in Delphi. It is supposed to be able to compile for Mac, but I dont have any experience with a Mac.
In the past I have written code in Java to be 'platform indepent'. I guess I could do that, but it would take a lot more time

[FrankB]

For anyone interested

[FrankB]

@FrankB, identifying that byte is remarkable.

It was my work for 40+ years.
I'm pleasantly surprised that you were able to modify that flag and that it showed as 'Saved'. Would it indeed behave better?

[Peobody]

Would it indeed behave better?

Now that is the million dollar question. I am not in a situation to do any creditable testing. So far this trip (4 days in), each time I have missed a via point I have simply restarted the route using CEP. This has created a different issue but I'll make that a new discussion.

[jfheath]

CEP - I find that creates the same situation as skipping a point - ie it 'arms' the XT ready for the next time you deviate from the route.

A different 'solution' is to turn off Auto-recalc, find the next route point that you will encounter, change it to a Via Point and select Go. Select the Via Point as the next destination. This will start the route again, beginning with navigating you to the nearest point ahead.

(You can change a shaping point to a Via without it altering anything else. It's changing a Via to a Shaping point that sometimes relocates and renames the point).