The routing is not great on a Garmin Edge
Hmm, I'm not sure I agree with that.
The routing on the Edge is exactly the same as the routing on any other Garmin device I've used.
The routing is really not much a function of the device: they all use ( approximately! ) the same algorithm. Differences in routing decisions are 99.999% down to differences in maps, and the granularity of the routes you create and download to the device.
If you obtain or create a route from a 3-rd party source ( like a routing website ) and dump it straight onto the device, then don't be surprised if the route is not what you expect when following it. The maps in the device will have different routing data to the maps on the website.
To get consistent routing between your route planning on the PC and route following on-the-ride, you really need to be planning the route using the same maps and same routing logic as the device will use on-the-day. That means using mapsource / basecamp.
My workflow is like this:
1) If a GPX is available, download it.
Load it up in Mapsource. Examine it for sanity. Mapsource will now have 1 track, in grey.
Notice how the track will not exactly follow the roads in Mapsource: this is due to differences in the mapping between the source of the GPX and Mapsource.
2) Create waypoints at the controls.
Zoom in on Mapsource, and place the control waypoints as accurately as possible.
Give them short names that can be distinguished if truncated on a small screen.
Mapsource will now have 1 track, and N waypoints.
3) Create routes.
I usually create a minimum of 2 routes: an 'out' and 'back'.
I tend to set the routing for 'car / motorbike' on both Mapsource, and the device.
Use the route tool to create a route using the 'start' waypoint, and the waypoint at the furthest control.
Mapsource will auto-route between these points, ( the wrong way most likely ) exactly on the roads.
Now, I need to 'force' the route to follow the track.
Drag the route to furthest extremities of the track, which is visible.
This creates intermediate 'via' points. The route will re-calculate.
Continue to drag sections of the route onto the track untill there are sufficient 'via' points to constrain the route onto the top of the track all the way round.
Repeat for as many routes as you wish to use.
Mapsource will now have 1 track, N waypoints and 2 or more routes.
4) Sanity Check.
Go round the entire ride in Mapsource, and be sure the 'route' is following the 'track'. The route will exactly follow the roads, the track will not.
5) Send to device.
Clear all old routes / tracks / tracklogs / waypoints from the device, and use Mapsource to upload the new track, routes and waypoints.
Set the track to 'always show on map', and it will appear in the background. I usually set it to a lime green colour to make it visible both day and night.
6) Follow the route.
Since the device will have the same maps and routing logic as Mapsource, the should be no surprises.
The purple route will obscure the underlying green track if all is well.
If the purple route deviates from the underlying green track, something has gone wrong with the routing.
Follow the green track untill it resolves itself.
