i fully agree with the explanation that TA provided above. I just came back from vacation on the big island of hawaii (very cool and very big island) my wife and i got lost in the middle of the island (dont ask how - it just happened- and whatever you do dont believe my wife when she says it was my fault) but i digress- i remember i had my n810 in my cargo shorts- fired it up and w/i a minute had a route back to our rented condo- (i was using the paid for wayfinder app)- of course i had previously received a fix when i got to the condo so the aGPS knew where i was-

my wife*now* approves of my toy....