Anyone use gps maps in their fish finders?  I am looking for a contour map of the snake river in my area.  Does anyone know of anything?

I have a map chip in my GPS/fish finder (Navionics Hot Map Premium -West).  Unfortunately, most of the rivers and reservoirs in Idaho don't have detailed maps.  If you go to the Navionics website and look at details on the map chips they will list what bodies of water have detailed maps are on each chip; if a body of water isn't listed, it will only have the basic map.  The only local lake that I have fished with a detailed map is Cascade Reservoir.  If you fish in Oregon, Washington or California you will find more waters with detailed maps.

That is what I am running into.  I can not find a anything with the places I fish listed, seems like a waste to get those cards.  I heard someone saying once that he was in a boat with a friend who ran the river here using a gps map with the channel marked on the map.  I need to go find this person and see what he has.

It is very difficult to find a contour map of any river. The river bottom changes so frequently that they are never current or accurate.