This isn't quite right; how much the locations actually vary between WGS84/NAD27 will depend on the exact location, but it's generally within 100m or so.
The difference between WGS84/NAD-83/NAD-27 datums has nothing to do with 100 point or 60 second scales; they in fact can all use the same representation of locations. Instead, how they differ is how they model the earth's shape as an ellipsoid - it's not the perfectly round sphere we all intuitively think of. A good basic description of this is at http://joe.mehaffey.com/maps.txt - there's a good number of other links to everything GPS under http://joe.mehaffey.com/ as well.
----- Original Message ----- From: "Matt Peckham" To: Sent: Tuesday, January 16, 2001 4:51 PM Subject: RE: [gpsstash] Re: WGS84!
> well, 72 degrees 00.000' would be identical in either format, where > 71degrees 59.500' would be a long long way off between the two. one > measures with a 100 point scale, the other with a 60 second scale. You > could be as far as 40% of a degree off in either direction. that could put > you in another state. > > My knowledge of the data is not 100%, but then again, I'm a lowly artist. > Matt