Fourbears wrote: ↑Wed Feb 09, 2022 9:13 pm
Any ideas as to what went wrong or do I need to put more waypoints in my routes? They were reasonably simple so I think I only had about 10 points, if that, in each route. Each one was about 200-250 miles on a variety of roads but in my logic I thought the XT would just stick to the route and recalculate it where necessary.
Yes - I have some answers for you. I'm still in the process of getting to grips with how it calculates with so little time out on the road with it. But some pretty good theories are developing from what I have found out. Covered below in response to your questions.
Fourbears wrote: ↑Wed Feb 09, 2022 9:13 pm
Over the last two days I have travelled 600 miles odd and had a couple of niggles with my XT. I created 3 routes in MRA and put some Via points in to tell me when I was coming up to fuel stops etc. However I miscalculated a fuel stop and had to look for one off route so used the category search and inputted a petrol station as my next stop in the active route. After refuelling I set off again and after about 3 or 4 miles realised that the XT was not taking me on MY route but a completely different on on motorways to my next Via point. I had to stop and reselect my rote on the XT and it took me on the route I planned.
As far as I can tell, the XT does not juts recalculate a route on a whim. But it does recalculate if you go off the route that it has plotted. And if you have imported from MRA then it is the XT that calculates the route - it doesn't use the one that was on the MRA map. It can't. MRA only exports the route points to the XT. Not the route itself.
The route that it calculates will be Fastest time. No matter what your XT is set to, the calculation mode is obtained from the route itself, not from the XT settings. (This is true for the 660, 590, 595) MRA doesn't have an option to select fastest time or shorter route - so the XT defaults to using fastest time. (Just like it defaults to using your XT motorcycle profile if the route doesn't specify a vehicle). Don't just dismiss that statement as an ill-informed opinion - check out the research I did on this -> /app.php/ZXT-P38 and subsequent pages. It is pretty intensive reading I know, but not as bad as it was testing it, writing it and then verifying it !
Now 'Fastest time' on the XT doesn't produce the same fastest time that other Zumos that I have owned would have done. My own suspicion is that this is in an effort to improve processing time, but I cannot possibly know that for certain. In a number of tests that I have carried out, 'Fastest Time' has often resulted in a route that is happy to take a massive detour in order to reach a faster road. In most cases this has resulted in a route that takes much longer than the fastest route that my 590 would have calculated
.
This means that when planning a route for the XT, you may have to spot the roads that it may aim for, and put shaping points in place to discourage it from heading for those. Just like you would do if you preferred route heads in roughly the same direction as a nearby motorway.
So when you wander off route, the XT will recalculate, and if there is a fast road inthe vicinity, it seems to prefer to head for that.
But - it will take you to your next route point. Or if by detouring, you missed a route point, it will head back to that.
Fourbears wrote: ↑Wed Feb 09, 2022 9:13 pm
Today it has done the same thing as I added a Via point in MRA and exported it to the XT before starting off. It then tried to take me on motorways again and I had to reselect the route.
Presumably when you reselected, you chose closest entry point ? This will find the point on the route that you are closest too (I don't know if it uses road distance or straight line distance to do this), and navigates you towards that point. This automatically misses out any shaping and via points that lie before the closest point.
If your satnav is doing weird things - then stopping the route and restarting it and selecting closest entry point is a pretty good solution. But always check the map. If U turns are disabled and the bike thinks that you are heading int he wrong direction, it has come up with some pretty weird ways of getting me to the closest point ! Not so if you allow U turns.
Fourbears wrote: ↑Wed Feb 09, 2022 9:13 pm
On my 3rd route back I missed a Via point by skipping it on the XT (as I didn't want to stop) and it then took me a completely different way to what I had planned.
If you Skip any route point the XT recalculates the entire route, not just the current section. That doesn't matter - it will come up with the same route that you had before - 'cos it had to calculate that too. But it does give the XT the opportunity to take traffic flow and riding behaviour into account - so it may be slightly different. The first bit of the route may well be very different - because you are not on the original route. You skipped a point. Previously it was taking you to the Via Point and then from there to the next route point. By skipping the Via, it is taking you direct to the route point after the Via. It may well find a completley different route. And as above, if there is a faster road nearby I reckon that it will head for it.
Now the crunch. I have an issue lodged with tech support for this situation at the moment. It seems that after pressing skip, the route that the XT produces seems to become fixed in some way (A bit like navigating a track). In a small number of experiments that I have carried out, if you deviate from that recalculated route after skip is pressed - it tries to take you back to the point from which you deviated. In my example I kept going on my chosen route for about 12 miles. I was 2 miles away from my next Via Point. The XT was insisting I go back to where I deviated and then follow its route. A total of 30 miles for the point that was just 2 miles ahead of me. It did eventually give in - when my next turning coincided with meeting the original route. It didn't do this on the same route if I deviated having not pressed Skip.
I don't know what the answer is to this.
Stopping the route and restarting with Closest Entry Point may well work. But CEP in may case would head me back until I was more than 6 miles from it.
Turning Recalc off would stop it - but I haven't tried it. You lose all naviagation instructiosn on the 590/5 if you do that and they resume once you meet up with the magenta route. It allows you to miss out Shaping Points in this way, but not Via Points.
Navigating a track (load the track and click 'Go!' is interesting and much more useful than I ever imagined that it would be.
Converting a track to a trip is also very interesting. The track stays in place if you deviate. But having deviated, as you move the XT will calculate where the closest point is on the route to your current position and it will navigate you to it. At first, the closest point will be behind you. But it keeps updating itself. You loses all of your route points with this method - but the track stays exactly where you put it.
Fxwheels wrote: ↑Tue Feb 15, 2022 10:34 pm
In my opinion you need to set closer (more) shaping points because after you miss a via point Garmin will recalculate using its own "mind" to the next one.
That is almost correct - but the term that you used (via point) makes it exactly wrong !!
If you miss out a shaping point by detoruing from the route, the satnav will give you instructions to navigate you to the next point in its list - ie the one that you have missed. But if you rejoin the magenta route after any missed shaping points, the satnav will navigate you to the next route point in its list from where you rejoin the route. It doesn't mind that you have missed them, and once on the route it forgets about the ones that are behind.
This is not the case with via points. If you miss out a via point and rejoin the route after the via point, it will take you back to it. It ill not take you to the next route point.
Even if you are on the route and heading in the right direction. The satnav will be calculating ways to get you back to the missed via And if you have disabled U turns, it will do this by taking you up side roads - which sound like odd, but genuine instructions. In this case allowing U turns alerts you to the fact that event though you are on the magenta line, the satnav is still trying to take you back.
Pressing skip will allow the XT to ignore the Via but that
seems to cause the problem I described above. The best option is to stop the route, restart it and choose closest entry point.
As I said - I haven't got definitive answers for some of the above. But the observations are well documented with screen shots, duplicated on second tests and reproduced on further tests on different routes. Nevertheless - these are only my own thoughts and observations of how my Zumo seems to behave.