Gps position in reference to map position.

[skeeterbrain]

I have an Echomap 94sv that I have a lakevu HD Ultra map card in.
My problem is that I get shown as being on dry land when I am in
some depth of water and maybe 40 to 60 feet from where my position shows.

[Larry3215]

That could be several things.

Which lake is it? Is it one with 1ft contours and a detailed shoreline? There could just be a significant error on that lakes location.

Have you compared your position when using the internal map instead of the Premium map? There have been some reports of discrepancies between the premium maps and internal maps.

You could have the Map Datum set wrong. It should be set to WGS84.

Settings/Preferences/Units/Map Datum

How and where is the MFD installed? Flush or not? If its flush mounted, or under a hard top, etc, the GPS antenna may not have a good view of the sky.

Go to Settings/System/GPS and look at the Sky View. It will tell you how many satellites are available and how good the fix is. The GPS error should be less than 20 ft. Mine is typically under 10 ft.

Also make sure GLONASS and WAAS are turned on if available.