Quote Originally Posted by warhawk View Post
I don't know if I made it clear or not. Most lake mapping is based on old topo maps made before the lake was dammed up. The new High Definition maps are made by surveying the lake with a survey boat outfitted with special electronics.

My navionics map was made off topo maps and while it's usually close, a lot of times it can be very inaccurate. My Garmin map is the Lakevu HD Ultra map. I have yet to find a place where it isn't spot on, and I've used it 10x more than I've used the Navionics map.

Also, with most maps you buy a map for one section of the country, Mid South in my case. But with Garmin the map covers the entire USA, I think it's 16,000 lakes.
Does the Garmin LakeVu HD Ultra map come on a chip that can be inserted into a hummingbird depth finder or is it just available on a Garmin GPS?