Zumo User Forums

Results of some recent and revised tests.
Same route. Some waypoints set to Vias. Some waypoints set to Shaping. Lots of additional adhoc points all set to Shaping.
Route had previously been recalculated and I know what to look for when it does. Two locations in particular are significant changes. I describe these below

Three tests carried out.

Phone with link to Explore database is turned off. XT2 cannot synch in this state.

1a. Check route after placing it onto the SD card and Importing it to the XT2. Do not load.
1b. Route imported. Current.gpx copied and checked. No changes on XT2 map. No changes to Current.gpx.
1b - Selected Go ! on route and then skipped start point. I could only find one change in the route - a very minor one. Took a copy of Current.gpx
Before test 1c, I stopped the test from 1b, deleted the route and reloaded the original. The route had not been altered.
1c. I imported the Test route again. So everything is as it was for test 2. Turned on the phone, established the link between Tread and the Zumo XT2. And saw that the XT2 had synch'd at 11:54 and again at 11:55. Closed down the XT2 and took a copy of Current.gpx

I stripped out all of the tags from the three current.gpx files. so that only the lat, long and name of the route points remained - separated by commas. (this is quite easy to do in Word with it Macro facilites and very sophisticated find and replace). Then imported the CSV files into an excel spreadsheet and got Excel to compare tests 1b with 1a and 1c with 1a. (1a is the original route)




1a is identical to 1b (I gave the lat/long values a bit of leeway of 0.00001) Names are unchanged, locations are unchanged. Route appeared to be unchanded on the maps.
1c is different. The green background represents the Via Points. These were all created as Waypoints, but two other points were created as Waypoints as well, but these were set as Shaping Points and they have changed as well. Every single shaping point has been moved and renamed.

Largely, these shaping points remained on the original route (but there are not man alternatives). Two important ones did not, and it altered the route - not significantly, but in a way that I did not want it to be altered. It seems that between Via Points, the system calculates a route close to the original, but improves it using its own preferences. And then puts in the same number of shaping points to keep the new route in place - but in completely new locations.

I've asked Excel to indicate with **** data that has been changed from T1a. and with Ok if it hasn't.

I think that this reproduces what @smfollen discovered in his tests. Just allowing the route to synch with the Explore database changes the route. I could not establish whether it did it after sending the data to the Explore database, or if it did it when it re-synched. That second statement should not happen surely - you don't expect your route to be sent, marked, corrected and then sent back. Whatever. it didn't happen before I turned on Tread.

But can I still use Tread to communicate - eg other, road works, road closures etc without having it Sync to Tread. I suppose I have to destroy the connection by resetting the explore database - so that it doesn't know how to connect me to it. Thats how I kept my XT2 for a while before I ventured into using Tread. These results suggest that the route behaves impeccably.

I think that this suggests that any gpx file from anywhere is going to suffer the same fate. I'd need to check that out.

--------------------------------

The significant alterations.


In both cases the route that I had planned follows the grey track. In the left hand picture I am heading North. The first shaping point in the bottom left is OK - I want to take that road. When that road meets the A685, I want to turn right. I had a shaping point in the area of the red circle, to force the route to take that road. There is a reason for this. I was leading a group of 10 motorcycles. If I turn left and then right onto the A6 then I am faced with a very busy right hand turn which is just after a a bend. To get 8 motorcycles out of that junction without gettting spread out by about 10 minutes is almost impossible. So I turn right and then head for the A6 on a much quieter junction - where traffic is helf up by frequently changing traffic lights.

The left hand picture shows a similar situation. I marked the road that I wanted to take with two shaping points - where the red circles are. The satnav deleted them and repalced them with two shaping points on the route that it preferred. A very narrow country lane with no way that a motorcycle can pass a car coming in the opposite directions, and often full of road debris / puncture risk .

Thank you for this @jfheath.
I guess I'm glad that you verified what I found, so I'm not losing my mind (at least not entirely).
I'm also disappointed that Tread does, in fact, change routes.

When I have a chance, I will pursue this with Garmin support, but I don't expect much resolution.
I will also submit the issue to the Garmin ideas page since Support has pointed me there more than once for other issues (e.g. RUT).

To be sure, I'm going to repeat the test when Tread isn't involved at all. Then with a gpx from MRA with tread installed and again with my hand built gpx file.
Then I'll see what a route created on Tread does, and a route exported from tread as a gox, and then loaded in to the tread app and/or Gpx folder

UPDATE

With Tread completely removed from Phone and Ipad, the same three stages worked perfectly. No changes to names (ish), no changes to coordinates.
SO I checked the route on transfer
I checked again on Import.
I checked again after loaiing it and saying Go
I cehcked again after skipping a route point.

In each case the data obtained from Current.gpx (the routes that the XT2 works with) was identical. Nothing had changed.

Except (there has to be an exception).
I have been very surprised to not that in my first test, all of my route points from BAsecamp had retained the name that I gave them when viewed on the XT2 screen.
But last time, all of my Via Points had been created as Waypoints. And only the Shaping points were moved. I wanted Via Points that had not been created as Waypoints first. I already had shaping points thathad been created as Waypoints.

Some of the route points had had their names altered. But every single one of them was a point that I had changed from the original route. Moved it to a slightly different location. Changed it to a Via. Changed it to a shaping. Only the ones that I had touched and all of the ones that I had touched lost the name that I gave them.

I wonder if this is why the behaviour appears to be so random ?

Interesting. I think what I'm seeing is consistent with that. Recently I have removed Tread from my phone. I have been using Basecamp to create routes, then exporting the gpx files to my hard drive and importing them to the XT2 via the sd card. My via and shaping points are typically not Waypoints. After import, I don't mess with anything. Names and locations do not change.

JFHeath wrote:
Only the ones that I had touched and all of the ones that I had touched lost the name that I gave them.

I think you are on to something here.
I have some ideas for further experiments but I won't be able to get back to this for at least a week. I'll update with whatever I find.

I'm getting similar behaviour. I'm using MyRouteApp now to plan routes now that I can't use BaseCamp with my new XT2. Importing GPX files, both 1.1 and 1.2 into the Tread app just caused issues. The app is so useless.

The (sort of) workaround is to manually add the GPX file to the XT2 directly, but then I occasionally get an error that the route cannot be calculated on the device. I also find, that if the Tread app syncs with the device, the routes will then be changed.

Absolutely infuriating.

I don't think that I've seen some of the problems, might it be that my XT2 is only seen in the phone Tread and not the phones "explore" app?

@Oop North John If I remember correctly, when setting up Tread, it asks for permission to sync with Explore. I suspect that the route changes occurs due to that sync, so if you have not allowed that, you will avoid the route changes, I THINK ?

smfollen wrote: ↑Sat Sep 14, 2024 12:35 pm @Oop North John If I remember correctly, when setting up Tread, it asks for permission to sync with Explore. I suspect that the route changes occurs due to that sync, so if you have not allowed that, you will avoid the route changes, I THINK ?

I’ll try that. It’s infuriating at the moment!

@SEllis Sorry to tell you this but as far as I know, there is no easy way to undo the Tread - Explore sync connection once it has been enabled. You apparently need to uninstall Tread from the phone, reset to XT2, then reinstall Tread and not allow it to sync.

See this thread https://www.zumouserforums.co.uk/viewtopic.php?t=2750 where @technoguppy wrote

Go to Settings / Device / Reset / Delete Data and Reset Settings