Okay, stupid questions.......I just got a Garmin 540 with the optional G2 chart card. How am I supposed to know what all the #'s and letters and symbols are? Is there a guise anywhere on the symbols and abbreviations? I cant find one anywhere! What is "5" and thenm theres #'s and letters all over too. round circles with stars???? HELP!!!!!

http://www8.garmin.com/cartography/m...mapLegend.html

I bought the chip. For a fisherman I can see its value. For a powerboater Its almost useless. It has street images loaded of citys,streets and points of interest on land. The nav feature of 3D is tough to use at 90mph. The maps and features preloaded in the 545 are plenty. Save your money on the chip