Course vs Route Recalculation

Thanks, appreciated, many of us have asked for a long time for the equivalent of a Course Recalculation option of OFF, like in Route Recalaculation. This is where a club course might be mandatory , has been pre planned, pre ridden by an organiser and they might know better than Garmin / OSM. You want the benefit of turn prompts etc but must stick with the planned course. Now we mostly have to disable turn guidance and just follow the course line, maybe with course points

Maybe "Prompt Only" might work , ignore any off course and hope it picks up the guidance again when you have self navigated along  the course  past the bit Garmin does not like?

Thanks, this is a very clear explanation. The kind of explanation you would expect in Garmin's user manual.

pjg61 said:

A Course in Garmin’s language is a pre-planned ride. 3^rd party platforms may call this a “Route” or something else. In contrast, a Route is what you get when you choose to navigate to a location on the device where the goal is to navigate you to a chosen location.

• Course Recalculation - This impacts what happens when the user is using turn guidance while navigating a course, and they go off-course. The recalculation refers to the route to get back to the course. The options are:

• Prompt with Auto Re-route: Will prompt the user with options, and will automatically select a route back to the course if the user does not select one within 10 seconds.
• Prompt Only: Will prompt the user with options, and will wait for the user to select one.
• Auto Re-route: Will automatically activate the most direct route back to the course.
• Auto Pause: Will automatically pause turn guidance until the user gets back onto the course.

• Route Recalculation - This impacts what happens when the user deviates from a route that is not associated with a user's pre-planned course. For example, they use turn guidance to navigate to a water stop, or they navigate back to the start of their activity. The difference is that the particular shape of the route is not important in this case - just the destination. The options are:

• Prompted: If the user goes off of the prescribed route, the device will ask the user if they want to recalculate the route to the destination before doing so.
• Automatic: If the user goes off of the prescribed route, the device will automatically readjust their route to get them from the new location to their chosen destination.
• Off: The device will not recalculate the route if the user deviates from the originally prescribed route.

pjg61 Thank you a lot for digging up into these concepts!
I also had same doubt on that.

To calculate the initial route associated to your pre-planned course, do you know if 1040, besides the course,  is also taking into account the Routing mode (Road, Mixed surface, MTB...), the popularity routing and calculation method (minimize distance/time) or these features only applies for routes to get from A to B or for recalculated routes?

Does the course recalculation takes you to the nearest (time/dist) point of your course or through the sortest path (time/distante) to the destination point ?

dasorsan said:

o calculate the initial route associated to your pre-planned course, do you know if 1040, besides the course,  is also taking into account the Routing mode (Road, Mixed surface, MTB...),

No, the Edges don't use the "avoidences" when calculating a route on a track.

The whole point of creating a track (planning a route) is to choose the exact path you want to use.

You wouldn't want the device second guessing your choices.

The track does have to follow roads/paths that are on the map installed on the device. The calculated route can do funky things where that isn't the case.

The track does have to follow roads/paths that are on the map installed on the device

Ok, I think I think it's becoming clearer to me. So, that is maybe the reason why my course and the calculated route by 1040 may differ, especially at crossroads, roundabouts junctions...

So.., do you mean if I manually make a course with a specific routable map and this this just he active one in 1040, the calculated pink route and my course would be exactly the same the 100% of the time and I won't get wrong TBT instructions? Because the calculated route for TBT is calculated from the active map in 1040, i guess...

My experience creating courses with routable maps, in Basecamp for example, is that sometimes I have to switch to manual mode (instead of automatically follow roads and paths) to avoid some broken routable nodes and useless detours o even not existing paths that I know they exists. In this case, I suppose that the 1040 TBT algorithm will take those detours instead my manually created section, won't it?

(sorry, for my English, not as easy to explain...)

That’s about right. (Your English is fine.)

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All the Edges work the same way.

The route calculation on the device “walks” along the track (from the file) and picks the nearest road/path that is on the installed map.

This process creates a second route (the lighter colored line). The second route is where the turn guidance (the big white arrows) comes from.

Note that track doesn’t have to follow the roads/maps exactly (the calculation will still work) but close works better.

If you go “off road” with manually-drawn sections, you’ll get “detours”. This is one of many reasons why having the maps screen displayed is better for navigation: you can see the deviations and follow the correct line.

If the map used to plan the route is different, you’ll get deviations. The maps the devices come with are based on Openstreetmap. Route planning websites provide Openstreetmap maps but that might not be the default.

Even with the same maps, deviations can happen but it’s unusual.

I think I will sleep better, you have made me understand many things

Then, do you mean de calculated route always relays on default preinstalled OSM maps on the device, even if they are disabled, instead of on my own non OSM enabled map? 

On the other hand, with the same underlying map (OSM map), I see that different platforms (plotaroute, RWGP, Garmin Connect... ) produces different routes to connect point A with B (at least when one is far away from the other) and it depends on some parameters too (car, bike, etc). So, I suppose that 1040 internal routing algorithm may produce different traces in some sections of your custom course, even if you use the same map that is active in the device to built your course. 

I wonder if the Garmin Connect routing algorithm will be the same than the internal Garmin1040 algorithm.