There are some quirks in the way the Garmin GPSMAP 64 does waypoint averaging
which need explanation. Two pages are used in the process: Waypoint Manager
and Waypoint Averaging. You should add these pages to your page sequence -
Menu - Menu - Settings - Page Sequence
Create a new averaged waypoint by positioning over the location and
selecting Create Waypoint from the Waypoint Averaging page.
This creates a new waypoint and immediately starts collecting a sample.
There is no way to change the waypoint name on the Waypoint Averaging
page. If you need to change the name do it from the Waypoint Manager.
Also, an apparent flaw in the software prevents display of the last
element of the sorted list of waypoints on the Waypoint Averaging page.
You can work around this by sorting the list by location. From Waypoint Averaging press -
Menu - Sort - Nearest
To start another sample select the waypoint from the Waypoint Averaging
page, position the receiver over the location and press Start. Always
check the Distance to Saved Location to make sure you have selected the
correct waypoint for averaging. It's best to collect subsequent samples
with different satellite constellations. Garmin recommends 90 minutes
between samples.
Subsequent samples can also be collected from the Waypoint Manager.
Select a waypoint and press -
Menu - Average Location.
You should always start a new averaged waypoint with Create Waypoint on the
Waypoint Averaging page. Collecting the initial sample by pressing Mark causes
the first sample to be unaveraged.