A good habit to get into is to recalculate any routes before sending them to the XT.
A quick (ish) way if recalculating all of your Basecamp Routes is to make an edit to the (motorcycling) profile. It recalculates every route in BC that uses that profile. Then you have to change it back again to what it was. But at least, you don't have to do each one individually.
I never have many routes on my satnavs. I regularly clear everything and transfer just the data that I want for a particular trip. One reason for doing this is that when you send more routes from Basecamp to the XT, it overwrites the temp.gpx file which contains the previously transferred routes. Those original routes are therefore no longer available to import again. Since editing an active route makes changes to the saved version, you cannot recover from accidental modifications if you are unable to re-import the route from temp.gpx.
GRC wrote: ↑Wed Sep 13, 2023 8:35 pmSuddenly they wouldn't transfer saying the map they were planned in didn't exist on my XT and it rerouted them in the transfer and screwed up the entire route.
I dont think that this has anything to do with the map update. Basecamp, and some other mapping programs (eg MyRouteApp when exporting with Gpx v 1.2) will remember exactly which roads you planned to ride. They do this by plotting hundreds of invisible route points between the shaping and via points to endure that the route the XT receives is identical to the route that was planned. Normally, if your maps are the same, the Zumo has no need to calculate the route. It has everything that it needs.
This has been the case with Zumos ever since I started using them with my 550.
This is fine until the Zumo needs to recalculate all or part of the route. Foe example, if you deviate from the plotted route; if you press skip; if you change routing preferences; if you allow traffic to affect your route;....
In these cases, the Zumo discards the current section of the plotted route and calculates a brand new one - with a new set if invisible 'ghost' points. This is exactly what you want - a new route to get to your next shaping or via point.
Unfortunately, while the above is true for the earlier Zumos - up to the 590/595 - the XT does things slightly differently.
It will often recalculate the entire route, not just the current section
The XT has a different way of calculating routes from the way that is used in Basecamp and on previous Zumo models.
The XT prefers to plot routes using 'faster' roads. What it means by this, I am not entirely sure - but if there is a major road nearby that can be used to take you to the next route point, it will use it. Even if this results in a longer trip that takes more time.
Think of it this way. Your Xt is set in landscape mode. You want to get from the bottom left corner to the bottom right corner. Across the top of the screen is a major road. The obvious way is to take a road aling the bottom if the screen. The XT will see that the major road across the top if the screen is closer than the bottom right corner, so it heads up the left of the screen, takes the major road across the top, and then goes down the right of the screen.
I dont know if this is what it actually does, but I have seen it prefer to go round three sides of a rectangle, just to use a major road.
I have challenged this behaviour, and apparently the routing behaviour is as Garmin intended.
So, what can you do about this.
Keep maps in synch. Bc and Zumo
Turn off auto recalc - but that doesn't help if the Zumo has to recalculate the route because maps are different.
Be aware of the issue when creating routes and use shaping points to make sure that the next shaping point is nearer than the closest major road. You don't have to fill your route with shaping points. Often 2 points along a particular route - spaced roughly evenly - will prevent the XT from visiting a point and then going back to the main road.
Place your points on the road to travel, not near a junction.
Use SP rather than VP - keep Via Points for key places - eg setting off after coffee stops.
Make a track of your route and transfer that to display on the XT screen. You will see the original track if the route is recalculated and you can follow that.
Practice uploading routes/tracks to the Zumo. Force the Zumo to recalculate the route - eg change it to a straight line route, then back to motorcycle. See what the Xt has done to it by comparing it with the track.
Doing this, you will get better at planning routes using any mapping software, to ensure the Zumo XT will take you where you want to go.
Or if you cant be bothered with all if that. Load the track and use that, or convert it to a trip.
