View Full Version : NAD & NAVD
2009-10-01, 04:07 PM
does anyonekow if there is a difference between NAD 83 & NAVD 88...
A huge difference.
To start, one is a horizontal datum, the other is a vertical datum.
Or perhaps I should say that one is a reference ellipsoid, while the other is a vertical datum.
NAD 83 will give you ellipsoid heights, but to be useful, those still need to be converted to an orthometric height, which might be in NAVD 88.
I have a paper where I go into a fair bit of detail about precisely what NAD 83 is. I don't really talk about NAVD 88 in this paper, but it might be helpful with understanding NAD 83. It's the "Working with Grid Coordinates" paper found here:
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