just a quick post to let you users of gps units in on a few things. first of all if you are using a GARMIN GPS there is probably a software update available for download on their web site. secondly, if you take a look in the lower left hand side of your TOPO map you will see somethere called MAP DATUM, you must set your GPS unit to this information, normally it is NAD 27. most units come with them set at WGS 84, if you try to use a map with this setting you can be off 200 meters, does not sound like much until you convert this to 600 feet. i use a program called MAPtech, i can order CD' s for what ever state or part of the state i want and print out my own topo maps, well worth the price. ok, that is it, thanks for reading and hopefully this will help someone.