working on one with my gps/fishfinder, embedded coordinates, color coded depth bands, the whole 9 yards... i have the first 2 bands all charted out 11 ft and 17 ft, next one will be 25... all submerged islands, point structure all layed over a google maps aerial photo... best map i've ever seen for conneaut lake... you can make your own with gps coordinates at gpsvisualizer.com . upload an excel file of your coordinates, maybe give them a color scheme, etc... best free tool ever.. also can make safety maps for hunting... get coordinates of your treestands, make a map, give to the wifey... if you're missing, the search team has an aerial photo with coordinates to start looking for you... i have just a garden variety humminbird gps/fishfinder combo and it can be just as useful as the navonics chip... it's free! next, to map out some deep holes on french creek with the kayak...