I just purchased a new boat and it has a 1197c on it. I was scrolling the GPS and noticed that only 2 lakes in my area show up in detail. I have not had a chance to get a Navionics chip yet. I know the previous user only fished these 2 lakes, but why wouldnt other lakes show up in detail in my area? Do i have to be on these lakes before the more detailed maps show up? Is there some function I have to perform to get the unit to reconize additional lakes? I am asking because I am going to fish a lake in the morning arrpx 75 miles from me and I scrolled the map to it and it just showed the outline of the body of water. Any help is appreciated