hotmaps [navionics} has a lot of info i bought a navionics chip the otherday at cabelas a 2008 edition east marked down to 99 bucks they had a nautipath for a few bucks more but that chip is just for the greatlakes but if that's all you want it for it did seem to have a little more detail on erie but the hotmaps chip had erie plus 12000 other lakes i guess it's all where you want to fish