OK - sorted.
The route will NOT alter the position of shaping points / via points (much) if the GPX files are placed on the SD card/GArmin/GPX folder
AND
The Tread App is disabled before they are imported.
(The SD card isn't a requirement that I know of. It's just that the XT2 cannot alter them if they are placed on the SD card )
As soon as the tread app is enabled on the iphone or the Android, then the route is synched to the Tread app, the Tread app changes the route and sends it back to the XT2. When the route is selected, the XT2 recalculates it. This seems to involve ignoring the shaping points, plotting the faster route between Via points, and then placing shaping point(s) so that they sit on the newly calculated route.
However, this doesn't happen If you don't wake up the Tread App. That is true for:
- Basecamp produced GPX files
- BC produced gpx files with the Subclass fields stripped out.
- Routes from anywhere with start stop and one shaping point
- Routes from anywhere with Start Stop and two shaping points.
- Identical route imported into the tread app, exported as a gpx file and loaded in the same way as any other gpx file.
- Identical route exported as a gpx from MyRouteApp.
It is not true for:
- Direct Routes - ie straight lines. The shaping points stay where they are.
- A route with a start, stop and Via points. The via points retain their name and stay where they are.
On the Android , the app can be left installed and running - as long as it does not show on the screen - ie it has to have been swiped off the screen. This means it is still running to process messages, traffic, weather, Group rides. But the BT connection still shows the Tread icon in blue. I have left the XT / phone in this state, repeatedly trying to synch and failing for a couple of hours without the route being altered. As soon as I open the tread app on the phone, it synchs and the route is changed a d the shaping points are moved.
The iPad - as soon as you swipe it off the screen - nothing is running and the Tread logo disappears from the XT2. The route remains intact. I don't know if there are any settings that will enable Tread to continue to run in the background for its other features. I know that the notification settings are controlled by the iOS software, rather than by the Tread app as is the case on the Android. I only have an iPad - not an iphone - so I cannot test most stuff.
Today, 3 weeks after sending a query to Garmin, I got a reply from Product Support about this. They want lots of information and evidence. I'll post it on here - probably a new thread - when I get that together. I had already started.
I've got to go back and check all this out with
@proofresistant's routes and observations. But I'm fairly sure. I've been fairly sure before though, so I'll check anyway !