Position on map elevation profile is offset

What was the source of the course file. There was a long running thread on this topic that turned out to be an issue with courses created on Strava that were introducing an offset . They fixed it, but if it is an old course that could be the issue.

The elevation and position come from course file so it is only as good as the DEM data used for the course creation.

I created the course the day of the ride on RWGPS. 

Would you be willing to share the course and activity file? You can use private message if you like, 

A similar behavior occurs on my 840. My location on the navigation screen is always 20+ meters to the east of my actual location during local rides. The displayed route is on the correct road. The navigation will show me on a neighboring road which becomes confusing in the congested, curvy road residential areas where I live. Seems to occur around where I live and not at remote locations. Not sure if it is location dependent or road density dependent. The recorded tracking is spot on.

The routes have been created in Garmin Connect. Here is the latest activity and course in which this issue occurred.

https://connect.garmin.com/modern/activity/16798752084

https://connect.garmin.com/modern/course/299887344

I am running firmware Version 21.18

Let me know if there is additional information I can provide to help.

Thanks,

Jim

That's sounds different than what I was describing.  In my case, my position on the map was correct, but the displayed elevation profile was off either behind or ahead of my position.  I saw another thread here about something that sounds very similar to your issue.The displayed position was offset in a consistent direction from the actual position. I believe they arrived at a solution but I don't remember what it was...maybe a map update or something...

Is "Lock on Road" enabled or disabled, it seems to cause issues like this.

Menu > Activity Profiles > [Select a Profile]* > Navigation > Routing > Lock on Road (best left disabled)

Is your device an Asian (China) model, these can have an off-set?

Does it occur near a military base where there might be powerful radar or other interference to GPS signal?

*If this helps the setting has to be done for each Profile.

PS: I presume you are loading the "course" and have Turn Guidance enabled. Even with a loaded course the 840 will still do its own "calculation" of the route using the enabled Routable Map, it does not always respect your planned (loaded) course, if it can not find a route between some points in the course it will attempt to find another route. In these cases there will be a darker (Magenta) course line for your loaded course and another lighter (pink) route which will also have the direction chevrons, the two lines may converge again later. A screenshot of your map would help in determining if this is the case. (below from a 830 but 840 will do the same)

Your suggestion of disabling "Lock on Road" fixed my problem.

I am in the US and using a US version of the device. I am not located near a military base.

The "Lock on Road" was an issue with and without a course loaded. In the screenshot below, I was actually located at the end of the cyan tracking line.

When "Lock on Road" was disabled, the "arrow" marker immediately moved to the correct point on the map which was on the exact road I was on. Seems to be a bug in the "Lock on Road" algorithm as the point location was exactly on the correct road and at least 20m from the incorrectly locked on road.

Thanks for your help! I won't be making as many wrong turns now :-)

I have a similar issue - My location on the navigation screen is always 20+ meters to the east of my actual location during local rides.

I am riding without a preloaded course and while my history line is correct, my position on map is with an offset, thus resulting many notifications (because there is always a trail adjacent to the road).

I have used the 'lock on road feature' since i am living in the northern Israel and we have GPS issues for a year now because of the war.

since reading this thread i have disabled the 'lock on road' option and I'll keep you posted if it solved the problem

the best what can you do in warzone or in jammed area is use the "Best accuracy" GNSS setting which is the MultiGNSS-MultiBand. Unfortunately the L1 bands are very vulnarable for jamming, the L5 is much better, the problem is that there is no such an option (maybe the Airoha AG3335 GNSS chipset can't work only with L5 bands) that "L5 bands only". With that the jamming is not exists or not so relevant (yet)

aweatherall do You have any knowledge about the possibility by hardware side for a future "L5 only" GNSS setting? 

I use best accuracy, but it seems like the 'lock on road' feature issue

my location is good but 20+- meters of road and as i continue to ride, my history line is accurate.

but having the location offset cause the sharp bend announcements, start climbing and other to pop with no reason unless you ride at the adjacent trail :-)