GPS DATUM

[Bduck]

On your GPS unit what GPS Datum frame is set? My Raymarine Element comes equipped with a menu of worldwide frames that can be installed depending location but the WGS 1984 (World Geodetic System 1984 (WGS 84)) is its default setting. My Raymarine Dragonfly does not come with this menu but uses the WGS 1984 frame which is a default setting for this unit. I'm assuming most units are set the WGS 1984 frame as default unless it can be changed with a menu provided in the unit like my Element. My question is do you use a different frame other than a default setting? Why?

North American Vertical Datum of 1988 (NAVD 88) - Vertical Datum - Datums - National Geodetic Survey (noaa.gov) 

[wiperhunter2]

I think you are correct Roger, all my boat GPS units are the same but I've had several hand held GPS units that are different and when I'm with someone else in their boat and mark a GPS location on my hand held unit, it will not correspond with my boat when trying to use those cords, one time it was around 1/4 mile different. Since I ran into that problem I just quit using my hand held units except for hunting which is mainly what I bought them for. I've never looked into changing my Datum frame.

[Bduck]

Curt, you may not be able to change your frame. My Raymarine Element I can change but not my Raymarine Dragonfly. I don't how many units are out there that can change frames unless I research into operation manuals on setting up. 

[2knots]

I use the the 84 on all my units

[dubob]

There is a good reason why WGS84 is the default on most if not all GPS sonar units.  If you want the technical details of why this is true, check out this tutorial link: https://gisgeography.com/geodetic-datums...d83-wgs84/

Most of the NGS maps that we use for hunting and trail riding are based on the NAD83 datum and most handheld units are more likely to have that as the default setting because they are mostly used on land vs water.