@Greenham From John Heaths excellent navigating with a Zumo Guide.
" MyRouteApp.
Very popular and provides a very good
solution. Possible issues for the Zūmo user :
Gpx v1.1
Track, Via Points and Shaping Points. No
Favourites. Zūmo has to calculate route - it
may end up being very different.
GPX v1.2
Track and Via Points. The plot of the route
is also transferred so the roads travelled are
identical to those plotted on the MRA map.
However, if the route is recalculated, it has
only the Via Points to work with. None of
the shaping points are transferred.
If you use this format, it is important not to
do anything that would make the Zūmo
recalculate the route.
Turn off Auto-Recalculate !
No Favourites are transferred to the Zūmo.
As stated above I use GPX1.1 and use lots of shaping points and display the track to ensure that my intended route and route as calculated by the XT match. The @ Martin-Wilcke method will also work well as long as you don't use recalculate to navigate back to the route.
Here is an example of a route (magenta line) and track (yellow line) I want the route to be the same as the track and travel along the B128 but because of the spacing of the shaping points and via points the Zumo XT "Faster Time" algorithm routes down the A28 and up the B45 which adds miles and time to the route. You can fix this in three ways
- Tap the map on the unit (as shown) to add additional shaping ponts to match the track
- Make sure as stated above that there is a waypoint on the B128 as you plan the route
- Use GPX1.2 and make sure that you don't recalculate the route when you are on it by switching off automatic recalculation.
As with all things its a bit of a learning curve and you are doing the right thing by testing and using the unit before you are on a live tour. That is very important.
Also when planning your routes put the start some way up the road from where you are actually starting as this ensures that the unit passes through the start point and does not try to take you back to the start as you have missed passing through it by a few metres.