Thanks again for the info!
How accurate are these models, say for an example if I wanted to mark some structure in the lake to come back and fish?
Will they get me within five feet of the structure or a city block?
Well, the answer to that is it depends.........It depends on how many sats the receiver is able to lock on to. This varies by conditions. On a bright sunny day, my E-trex Legend will normal say accuracy to with in 16 feet and I think I've seen it as low as 13 feet. As I travel along, the accuracy varies as the unit looses and regains satellites. This occurs as clouds pass, being under trees or other obstructions, and the fact that when a turn is made, say from going east to going west then the unit could loose a satellite in the eastern sky but will hopefully regain one in the western sky. The just of it is, at the frequency the GPS system operates on, the receiver needs to be able to see the satellites........
So, accuracy will vary with conditions.......but under average conditions my opinion would be from 20 to 32 feet........but there are times when the receiver is unable to aquire enough satellites to be able to determine where you are......this doesn't occur frequently but thick canopys in a hardwood forest can reduce conditions to this point. Uncle Sam is working to add sattellites to the system and everyone they adds should improve the system......