Zumo XT "Cannot Calculate the Route"

[Grabcon]

Hi new to forum, not new to Basecamp and Satnav.

I just bought a Zumo XT after my Zumo 660LM touch screen started to fail and inopportune times. The other day I created a route in Basecamp something I have done thousands of times. The route was a loop about 250 miles. All types of roads. I transferred to the Zumo XT SD Card, went to import and got a "Cannot Calculate the Route" (CCR) message. I went back to Basecamp and I split the route about half way. Deleted the original gpx file on the SD card and transferred the two new gpx files. Did the import and the first half of the route imported fine. The second half I received the CCR message.

So where do I go from here to chase down why the file didn't import? I am sure I can go and readjust the route and try to resolve, but are there others in the continuum resolved this issue? I never had issues like this on the 660.

Thanks

[Peobody]

This discussion may help. viewtopic.php?p=6131

[Grabcon]

Thanks for the link but not much help. These are dead simple routes very few points. In fact the route that fails only has a handful of point. The route in Green is the route that failed to import, the other worked fine, plus it had more complex road types. Hwys to dirt. Failed route all paved roads and interstates.

The failed route was basically calculated by Basecamp.

[Peobody]

This one calculated for me (wish I could make the XT think I was somewhere else so it wouldn't calculate from NC). I know that I don't have the same points as you but I think they are in the ballpark. I don't have a clue why yours doesn't calculated. The only thing I can suggest is try using different points.
Edit: I don't know if it's relevant but I'm using map CN NA NT 2023.2 in BC and on the XT.

[Grabcon]

Try this gpx file and see what happens.

Carr House to San Manuel 2.GPX

(169.17 KiB) Downloaded 196 times

[Peobody]

That one fails with "Cannot Calculate the Route". This one works though. I loaded yours into BC and made 3 minor point changes. I don't know which one of them it didn't like nor can I explain why one works and one doesn't.

Carr House to San Manuel 3.gpx

(174.6 KiB) Downloaded 189 times

[Peobody]

Let me just add that if you spend any time in this forum you will come to know that there are a number of behaviors in the XT that we just don't understand. Some folks work hard at trying to figure them out but at the end of the day our only choice is to do what need to be done to get the XT to do what we want it to do. Even then, there are no guarantees, especially when it recalculates. That is something we are learning to avoid.

[Grabcon]

Peabody, thanks for all of your responses. Although your last response about the XT behavior and no real resolutions is bothersome. These are expensive units and Garmin should provide at a minimum an error log when building imported routes.

But for me I did find the issue, see attached, the two circled items. It was a stop point, basically an in and out, coffee break etc. I split the original route in Basecamp into three and narrowed it down to the circled area. Joined all back together for the original loop and the route did build and looks correct. But since I have not used the build to actually navigate the route I really don't know if it will work. It should, but like the 660 there were times that things didn't go according to plan.

[Peobody]

Identifying that WP as the problem is surprising considering that I left it untouched in my version. Perhaps my creation of new points on either side of it that were slightly further away caused mine to work. Regardless, I'm glad you got it to calculate.

Although your last response about the XT behavior and no real resolutions is bothersome. These are expensive units and Garmin should provide at a minimum an error log when building imported routes.

It is bothersome to us all, and it can be very frustrating. AFAIK, the problem you encountered with calculating the route is rare. Most of the issues are with what the XT produces when it recalculates routes. It is often illogical. If the XT is configured for Faster Time a recalc will route over faster roads often at the expense of an unreasonable number of extra miles. Be sure the Off-Route Recalculation in the XT is set to Off or Prompted. Hint: skipping a point will cause the XT to recalc to the end of the route not just to the next point. One technique that helps with unwanted recalcs is showing a track of the route on the map along with the route itself. It allows you to see when a recalc results in the new route deviating from original (the track). This trick is worth looking into if you aren't familiar with it. There is a lot to like about the XT but a lot of frustrations too.

[Grabcon]

Peabody, even on my 660 I have had recalculate off forever so the illogical results I am familiar with. I almost exclusively use Basecamp for my motorcycle routing. I have learned over the years to use a lot of shaping point forcing the route in the satnav to follow my specific route that I have planned.

The biggest issue I have found over the years is the map data. Not all map data sets are equal and because of that different results may happen. I have not used OSM but I do use Basecamp and google maps together and have found street classifications and street names not are always the same. Street classifications and the routing algorithms are one of the culprits with different route results. Also one would think that since both Basecamp and the XT and other Satnav units from Garmin would use the same routing algorithms and produce the same results regardless of where they are created. If the map data are the same data sets. If the map data sets are different the results have the potential to be different.