Foretrex 801 'To Course' Behavior

[omenlabs]

This may not be just related to the Foretrex 801, but I can't find any documentation about how "To Course" is supposed to work.

"To Course" only differs from "Bearing" when I am in motion (for example in a car and navigating to a waypoint a few miles away). When I stop and the Foretrex switches to the magnetic compass, "To Course" changes immediately to be the same as "Bearing". This strikes me as odd.

I haven't tested this behavior on my GPSMap 66i yet, but I guess that is the next step. I'm wondering if anyone out there understands how "To Course" is supposed to work. I did verify that when it did give me a direction other than the current bearing to the waypoint, it did do a nice job of getting me to intersect the original course.

[GPSrChive]

The current Foretrex 801 User Manual indicates:

To Course - The direction in which you must move to get back on the route. You must be navigating for this data to appear.

This is the standard Garmin definition for the 'To Course' data field.

We agree the behavior described does not seem correct.

We do not have a Foretrex 801 to test with, so if others can confirm the behavior reported in the post above, we can submit to Garmin for investigation.

[omenlabs]

I just played around with "To Course" on my GPSMap 66i. It has the same behavior--"To Course" becomes the bearing when I am not moving. But once I started walking it would change. I suspect the calculation may have something to do with Velocity Made Good, but I still haven't found a good description. I've even tried poking around in older manuals (like for the eTrex Legend). I found a nice description of the 'Bent Pointer' mode that is the default on the Foretrex compass when navigating (the pointer bends to indicated the direction of an upcoming turn) that is not documented in the short Foretrex manual, but no luck on "To Course".

[axd1967]

I tried walking a small route of about 100m with an 801 (v2.10).

It seems as if the unit tries to send the user along an arc, while one would expect a straight line towards the course, followed by a turn towards the next waypoint.