Yes, gps will show you creek channels, ledges, flats, drop offs, and you can mark your brush piles. I have had the Garmin 43dv on my boat since last December and can tell you for a $300 unit it is awesome. It has GPS and DownVu as well as standard sonar. You can use split screen in different configurations or view the entire screen with DownVu, GPS, or standard sonar only. Lewisville and Ray Bob are both Garmin mapped with 1' contours. Also, Garmin is so easy to use. If you are new, it can save you a lot of frustration. Good luck!
SE Kansas grass grower
2008 NCAA Mens Basketball Champions