Just wandering if anyone has a Garmin GPS unit that's loaded with lake TOPO information. As best I can tell the info would be on a card (SD card or something of that nature) which they call "US Recreational Lakes with Fishing Hotspots". If so, my question is, is the topo info really good or is it sorta vague? We have a Garmin 172 console mounted gps unit and the card I'm describing costs about $120.00. We also have a Lowrance sonar unit that can double as a GPS. I know that the Lowrance software provides good bottom detail, but we'd have to purchase an antenna and the SD card in order to make "it" work. That's seems like it's going to cost about $350.00-$400.00. If I could determine that the Garmin bottom detail is good, well, I could get "out the door" for about $250.00 less. Any info would be much appreciated.