I just loaded a section of a map from CalTopo 2011 onto my GPSmap 78SC into internal memory, and disable all other maps. I set detail to MOST, but although I can see other features, the lakes are not displaying as blue bodies of water on the map. If I move the cursor to where the lake should be, it labels it, but it shows only as a blank on the topo, not a blue lake. I.e., it looks as if it is a meadow on the topo. None of the lakes in this map segment are showing up on my GPS display, at the highest zoom in level, although I can see them all in Basecamp on my PC. What is wrong?