The GUNDER device allows scuba divers to navigate underwater using a surface towed GPS buoy. The GUNDER (Graphical Underwater Navigational Device Environment Recorder) is a real-time GPS system that allows a diver to navigate with features similar to most dive computers. Such features include compass, depth and temperature. This system however is unique in that it contains a navigational map interface. Users are able to mark underwater dive sites and return to them using the GUNDER device. This is not only useful for recreational divers but for underwater archeological mapping as well. The primary use of the GUNDER is its ability to take captured data and geo-reference it to camera imagery for photogrammetric modeling of underwater environments.