I asked this question in another forum, but didn't get a satisfactory answer. I have checked out Garmin, Lowrance, and Magellan. Lowrance has the Airmap 600C, which is the closest for aviation purposes, and price range, but I couldn't get any good info for its' terrestrial use, if it even has any, for that particular model. Could never get through the Lowrance phone line to talk to a customer service rep, after 2 weeks of trying, but was always put on an indefinite automated hold! I also checked out the Garmin 96C. The Lowrance seems to have more for less. As a student GA(general aviation) pilot, I am interested in a handheld unit that would serve me in the air, as well as if I had to ditch in a forrest, or unknown area, etc,and lived to walk my way out! Just trying to find a unit that has the best of both aviation and terrestrial applications. Want to stay within the 300-500 dollar range. Can be flexible within a 100 dollars more if necessary. Any good suggestions?