Courses and navigation

Actually I have a theory. If you go to Garmin Connect (or any other route planner) and create a course from Start A to End B with only these two points, but with alternative ways to reach point B, it can go wrong, since the navigation part would try to find the fastes (or shortest if you have set it up) from A to B.

But if you create the course with a lot of course points between A and B then you would have a better chance for not having the 820 navigation part to be confused. So in all a course with a lot of points would be the best.

Can someone confirm that courses with a lot of point (marks on the map) works better with turn by turn navigation?

This is a perennial frustration with Garmin units -- their turn-by-turn calculates what it thinks is right, rather than carefully following your mapped-out route. Having said that, do you have "road cycling" set as your routing option (as opposed to mountain biking)? Also, although it won't change the original TBT calculation, do you have "recalculate" set to off, so when you follow your route (which is easier to do, IMO, if you use 3D in mapping options and get a big white line for your mapped route), you don't get re-routed?

I think your theory may help, but I don't recall if that worked for me while I had the 820. I returned it and got the Explore 1000, which has a "direct routing" option which seems (I say "seems"!) to calculate the TBT as I mapped it better than "road cycling". Certainly Garmin's instructions will never tell you! In any event, the 820 doesn't have the "direct routing" option.

This is a perennial frustration with Garmin units -- their turn-by-turn calculates what it thinks is right, rather than carefully following your mapped-out route. Having said that, do you have "road cycling" set as your routing option (as opposed to mountain biking)? Also, although it won't change the original TBT calculation, do you have "recalculate" set to off, so when you follow your route (which is easier to do, IMO, if you use 3D in mapping options and get a big white line for your mapped route), you don't get re-routed?

I think your theory may help, but I don't recall if that worked for me while I had the 820. I returned it and got the Explore 1000, which has a "direct routing" option which seems (I say "seems"!) to calculate the TBT as I mapped it better than "road cycling". Certainly Garmin's instructions will never tell you! In any event, the 820 doesn't have the "direct routing" option.

Thank you Roger. This means that the turn by turn feature combined with courses is useless. You will have to use the map screen to follow a course. I simply can't understand Garmin can get away with this...

This is a perennial frustration with Garmin units -- their turn-by-turn calculates what it thinks is right, rather than carefully following your mapped-out route.

What you load to the unit is a track (the file doesn't have any street information). The Garmins have to "walk" the track to figure out what roads it appears to be following.

Having said that, do you have "road cycling" set as your routing option (as opposed to mountain biking)?

The avoidance settings aren't used when using a course.

So in all, why does the turn by turn navigation want me to follow tracks and roads that does not belong to the course I have loaded?

What you are describing doesn't see quite right.

Can you PM me with one of the routes you had a problem with?

The file you load to the Garmin is a track (there is no street information in the file). The Garmin has to "walk" the track to figure out what roads the track appears to be following.

If there are alternative roads close by, the Garmins sometimes choose a short cut but that not that common.

It doesn't matter what course planner you use (Connect, Gpsies, RWPGPS).

The 820 comes with maps based on Openstreetmap (OSM) data. Things work better if the same map is used for planning the course. Garmin connect lets you choose to use OSM maps (but uses something else by default).

Can someone confirm that courses with a lot of point (marks on the map) works better with turn by turn navigation?

No, the number of control points doesn't matter. Those are not included in the file that is loaded to the Garmin (the Garmin knows nothing about them).

Keep in mind that the Garmins use track files for navigation. Track files have lots of points (many, many more than the control points you are talking about).

What you are describing doesn't see quite right.

Can you PM me with one of the routes you had a problem with?

The file you load to the Garmin is a track (there is no street information in the file). The Garmin has to "walk" the track to figure out what roads the track appears to be following.

If there are alternative roads close by, the Garmins sometimes choose a short cut but that not that common.

It doesn't matter what course planner you use (Connect, Gpsies, RWPGPS).

The 820 comes with maps based on Openstreetmap (OSM) data. Things work better if the same map is used for planning the course. Garmin connect lets you choose to use OSM maps (but uses something else by default).


No, the number of control points doesn't matter. Those are not included in the file that is loaded to the Garmin (the Garmin knows nothing about them).

Keep in mind that the Garmins use track files for navigation. Track files have lots of points (many, many more than the control points you are talking about).

Thank you for clarifying how it works! I have now examined the courses I downloaded from gpsies. And I believe you are right. The problem is when there is a service road or minor track along the bigger road it has gone wrong at many points, and the planner tool has chosen the gravel roads and off-trail tracks instead of the main road. And then I off course cannot blame the 820 ;-) So from now on, I will create and check my own courses instead. I will let you know if I still have the problem.

But you say "If there are alternative roads close by, the Garmins sometimes choose a short cut but that not that common". I am still pretty sure that this is what I experienced a couple of times... And that is a bit contradictory to how you say it works. But thank you again for explaining!

But you say "If there are alternative roads close by, the Garmins sometimes choose a short cut but that not that common". I am still pretty sure that this is what I experienced a couple of times... And that is a bit contradictory to how you say it works. But thank you again for explaining!

It's not really contradictory.

There are two ways the Garmin can pick the wrong road.

1) If the track was created using a map that is different than the map on the device. Maps don't always locate roads in exactly the same place. If there's a side path on the device map, the track might just happen to be closer to it than to the road on the device map. This is why you want to plan the route using the same map as installed on the device.

2) The device "walks" the route in "steps". If there's a short cut between the "steps", the Garmin just might use it. This is apparent on the device because the short-cut will show up as a "lighter" magenta line that separates from the "darker" magenta track line. For most people, this doesn't happen too often. It sort if depends on what the roads/paths are like (it probably occurs more often in cities than in the country). It doesn't matter too much: either route will get you where you need to go. In any case, there's nothing one can do to prevent this from happening. I suspect it's a consequence of making the route calculation not take too long to complete.

This shows an example of a shortcut.

https://forums.garmin.com/forum/into-sports/cycling/edge-1000-aa/66782-edge-1000-and-tcx-files/page2?95388-Edge-1000-and-TCX-files=